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Chapter 54: Estimating and Comparing Length

Learn Grade 2 mathematics with very-beginner explanations, original worked examples, practice, reasoning, and review.

Grade 2Very Beginner Friendly10 Examples Per Topic30 Q&APractice + Review
Estimated reading time0% read
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Chapter Overview

This chapter teaches Estimating and Comparing Length with simple explanations, visual thinking, worked examples, practice, and review.

54.1 Estimating in centimetres

Length tells how long something is. Standard units such as centimetres and metres make measurements comparable. Use objects, drawings, number lines, tables, or number sentences when useful.

10 Worked Examples with Answers

Worked Example 1

Problem: An activity starts at 6:00 and lasts 30 minutes. When does it end?

  1. Move forward by the elapsed time.

Very beginner explanation: Elapsed time tells how long passes.

Answer: 6:30

Worked Example 2

Problem: An activity starts at 7:00 and lasts 30 minutes. When does it end?

  1. Move forward by the elapsed time.

Very beginner explanation: Elapsed time tells how long passes.

Answer: 7:30

Worked Example 3

Problem: An activity starts at 6:00 and lasts 30 minutes. When does it end?

  1. Move forward by the elapsed time.

Very beginner explanation: Elapsed time tells how long passes.

Answer: 6:30

Worked Example 4

Problem: An activity starts at 5:00 and lasts 60 minutes. When does it end?

  1. Move forward by the elapsed time.

Very beginner explanation: Elapsed time tells how long passes.

Answer: 6:00

Worked Example 5

Problem: An activity starts at 3:00 and lasts 60 minutes. When does it end?

  1. Move forward by the elapsed time.

Very beginner explanation: Elapsed time tells how long passes.

Answer: 4:00

Worked Example 6

Problem: An activity starts at 7:00 and lasts 60 minutes. When does it end?

  1. Move forward by the elapsed time.

Very beginner explanation: Elapsed time tells how long passes.

Answer: 8:00

Worked Example 7

Problem: An activity starts at 6:00 and lasts 60 minutes. When does it end?

  1. Move forward by the elapsed time.

Very beginner explanation: Elapsed time tells how long passes.

Answer: 7:00

Worked Example 8

Problem: An activity starts at 5:00 and lasts 30 minutes. When does it end?

  1. Move forward by the elapsed time.

Very beginner explanation: Elapsed time tells how long passes.

Answer: 5:30

Worked Example 9

Problem: An activity starts at 9:00 and lasts 60 minutes. When does it end?

  1. Move forward by the elapsed time.

Very beginner explanation: Elapsed time tells how long passes.

Answer: 10:00

Worked Example 10

Problem: An activity starts at 3:00 and lasts 60 minutes. When does it end?

  1. Move forward by the elapsed time.

Very beginner explanation: Elapsed time tells how long passes.

Answer: 4:00

54.2 Estimating in metres

Length tells how long something is. Standard units such as centimetres and metres make measurements comparable. Use objects, drawings, number lines, tables, or number sentences when useful.

10 Worked Examples with Answers

Worked Example 1

Problem: Use 2 and 15 to make a simple example about Estimating in metres.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Estimating in metres.

Worked Example 2

Problem: Use 11 and 7 to make a simple example about Estimating in metres.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Estimating in metres.

Worked Example 3

Problem: Use 8 and 4 to make a simple example about Estimating in metres.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Estimating in metres.

Worked Example 4

Problem: Use 3 and 9 to make a simple example about Estimating in metres.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Estimating in metres.

Worked Example 5

Problem: Use 3 and 5 to make a simple example about Estimating in metres.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Estimating in metres.

Worked Example 6

Problem: Use 12 and 9 to make a simple example about Estimating in metres.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Estimating in metres.

Worked Example 7

Problem: Use 7 and 12 to make a simple example about Estimating in metres.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Estimating in metres.

Worked Example 8

Problem: Use 11 and 19 to make a simple example about Estimating in metres.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Estimating in metres.

Worked Example 9

Problem: Use 16 and 15 to make a simple example about Estimating in metres.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Estimating in metres.

Worked Example 10

Problem: Use 3 and 18 to make a simple example about Estimating in metres.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Estimating in metres.

54.3 Using benchmarks

Using benchmarks is a Grade 2 math idea best learned with simple numbers, objects, drawings, and clear words. Use objects, drawings, number lines, tables, or number sentences when useful.

10 Worked Examples with Answers

Worked Example 1

Problem: Use 18 and 10 to make a simple example about Using benchmarks.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Using benchmarks.

Worked Example 2

Problem: Use 18 and 19 to make a simple example about Using benchmarks.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Using benchmarks.

Worked Example 3

Problem: Use 6 and 15 to make a simple example about Using benchmarks.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Using benchmarks.

Worked Example 4

Problem: Use 10 and 8 to make a simple example about Using benchmarks.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Using benchmarks.

Worked Example 5

Problem: Use 12 and 6 to make a simple example about Using benchmarks.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Using benchmarks.

Worked Example 6

Problem: Use 15 and 15 to make a simple example about Using benchmarks.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Using benchmarks.

Worked Example 7

Problem: Use 18 and 11 to make a simple example about Using benchmarks.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Using benchmarks.

Worked Example 8

Problem: Use 15 and 3 to make a simple example about Using benchmarks.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Using benchmarks.

Worked Example 9

Problem: Use 6 and 17 to make a simple example about Using benchmarks.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Using benchmarks.

Worked Example 10

Problem: Use 2 and 19 to make a simple example about Using benchmarks.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Using benchmarks.

54.4 Longer and shorter

Longer and shorter is a Grade 2 math idea best learned with simple numbers, objects, drawings, and clear words. Use objects, drawings, number lines, tables, or number sentences when useful.

10 Worked Examples with Answers

Worked Example 1

Problem: Use 6 and 3 to make a simple example about Longer and shorter.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Longer and shorter.

Worked Example 2

Problem: Use 10 and 7 to make a simple example about Longer and shorter.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Longer and shorter.

Worked Example 3

Problem: Use 7 and 19 to make a simple example about Longer and shorter.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Longer and shorter.

Worked Example 4

Problem: Use 14 and 9 to make a simple example about Longer and shorter.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Longer and shorter.

Worked Example 5

Problem: Use 11 and 10 to make a simple example about Longer and shorter.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Longer and shorter.

Worked Example 6

Problem: Use 11 and 19 to make a simple example about Longer and shorter.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Longer and shorter.

Worked Example 7

Problem: Use 4 and 7 to make a simple example about Longer and shorter.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Longer and shorter.

Worked Example 8

Problem: Use 1 and 18 to make a simple example about Longer and shorter.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Longer and shorter.

Worked Example 9

Problem: Use 7 and 15 to make a simple example about Longer and shorter.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Longer and shorter.

Worked Example 10

Problem: Use 4 and 4 to make a simple example about Longer and shorter.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Longer and shorter.

54.5 Same length

Length tells how long something is. Standard units such as centimetres and metres make measurements comparable. Use objects, drawings, number lines, tables, or number sentences when useful.

10 Worked Examples with Answers

Worked Example 1

Problem: Use 4 and 10 to make a simple example about Same length.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Same length.

Worked Example 2

Problem: Use 12 and 9 to make a simple example about Same length.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Same length.

Worked Example 3

Problem: Use 5 and 9 to make a simple example about Same length.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Same length.

Worked Example 4

Problem: Use 4 and 8 to make a simple example about Same length.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Same length.

Worked Example 5

Problem: Use 2 and 20 to make a simple example about Same length.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Same length.

Worked Example 6

Problem: Use 12 and 19 to make a simple example about Same length.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Same length.

Worked Example 7

Problem: Use 10 and 15 to make a simple example about Same length.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Same length.

Worked Example 8

Problem: Use 3 and 13 to make a simple example about Same length.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Same length.

Worked Example 9

Problem: Use 11 and 16 to make a simple example about Same length.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Same length.

Worked Example 10

Problem: Use 4 and 18 to make a simple example about Same length.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Same length.

54.6 Comparing estimates and measurements

Estimation gives a nearby amount. The nearest ten is the multiple of ten closest to the number. Use objects, drawings, number lines, tables, or number sentences when useful.

10 Worked Examples with Answers

Worked Example 1

Problem: Which ten is closer to 64: 60 or 70?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 60

Worked Example 2

Problem: Which ten is closer to 65: 60 or 70?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 70

Worked Example 3

Problem: Which ten is closer to 69: 60 or 70?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 70

Worked Example 4

Problem: Which ten is closer to 98: 90 or 100?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 100

Worked Example 5

Problem: Which ten is closer to 23: 20 or 30?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 20

Worked Example 6

Problem: Which ten is closer to 70: 70 or 80?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 70

Worked Example 7

Problem: Which ten is closer to 47: 40 or 50?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 50

Worked Example 8

Problem: Which ten is closer to 77: 70 or 80?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 80

Worked Example 9

Problem: Which ten is closer to 76: 70 or 80?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 80

Worked Example 10

Problem: Which ten is closer to 31: 30 or 40?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 30

54.7 Choosing a useful benchmark

Choosing a useful benchmark is a Grade 2 math idea best learned with simple numbers, objects, drawings, and clear words. Use objects, drawings, number lines, tables, or number sentences when useful.

10 Worked Examples with Answers

Worked Example 1

Problem: Use 3 and 17 to make a simple example about Choosing a useful benchmark.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Choosing a useful benchmark.

Worked Example 2

Problem: Use 11 and 12 to make a simple example about Choosing a useful benchmark.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Choosing a useful benchmark.

Worked Example 3

Problem: Use 1 and 17 to make a simple example about Choosing a useful benchmark.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Choosing a useful benchmark.

Worked Example 4

Problem: Use 3 and 8 to make a simple example about Choosing a useful benchmark.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Choosing a useful benchmark.

Worked Example 5

Problem: Use 19 and 2 to make a simple example about Choosing a useful benchmark.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Choosing a useful benchmark.

Worked Example 6

Problem: Use 5 and 10 to make a simple example about Choosing a useful benchmark.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Choosing a useful benchmark.

Worked Example 7

Problem: Use 9 and 7 to make a simple example about Choosing a useful benchmark.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Choosing a useful benchmark.

Worked Example 8

Problem: Use 1 and 18 to make a simple example about Choosing a useful benchmark.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Choosing a useful benchmark.

Worked Example 9

Problem: Use 12 and 16 to make a simple example about Choosing a useful benchmark.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Choosing a useful benchmark.

Worked Example 10

Problem: Use 8 and 18 to make a simple example about Choosing a useful benchmark.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Choosing a useful benchmark.

54.8 Finding a difference in length

Subtraction can mean taking away, finding a difference, or finding a missing part. Addition can check the answer. Use objects, drawings, number lines, tables, or number sentences when useful.

10 Worked Examples with Answers

Worked Example 1

Problem: Find 110 − 27.

  1. Start with the larger number.
  2. Take away or count up.
  3. Check with addition.

Very beginner explanation: Subtraction finds what remains or the difference.

Answer: 83

Worked Example 2

Problem: Find 30 − 5.

  1. Start with the larger number.
  2. Take away or count up.
  3. Check with addition.

Very beginner explanation: Subtraction finds what remains or the difference.

Answer: 25

Worked Example 3

Problem: Find 88 − 73.

  1. Start with the larger number.
  2. Take away or count up.
  3. Check with addition.

Very beginner explanation: Subtraction finds what remains or the difference.

Answer: 15

Worked Example 4

Problem: Find 97 − 49.

  1. Start with the larger number.
  2. Take away or count up.
  3. Check with addition.

Very beginner explanation: Subtraction finds what remains or the difference.

Answer: 48

Worked Example 5

Problem: Find 55 − 48.

  1. Start with the larger number.
  2. Take away or count up.
  3. Check with addition.

Very beginner explanation: Subtraction finds what remains or the difference.

Answer: 7

Worked Example 6

Problem: Find 131 − 43.

  1. Start with the larger number.
  2. Take away or count up.
  3. Check with addition.

Very beginner explanation: Subtraction finds what remains or the difference.

Answer: 88

Worked Example 7

Problem: Find 78 − 30.

  1. Start with the larger number.
  2. Take away or count up.
  3. Check with addition.

Very beginner explanation: Subtraction finds what remains or the difference.

Answer: 48

Worked Example 8

Problem: Find 77 − 23.

  1. Start with the larger number.
  2. Take away or count up.
  3. Check with addition.

Very beginner explanation: Subtraction finds what remains or the difference.

Answer: 54

Worked Example 9

Problem: Find 147 − 121.

  1. Start with the larger number.
  2. Take away or count up.
  3. Check with addition.

Very beginner explanation: Subtraction finds what remains or the difference.

Answer: 26

Worked Example 10

Problem: Find 22 − 1.

  1. Start with the larger number.
  2. Take away or count up.
  3. Check with addition.

Very beginner explanation: Subtraction finds what remains or the difference.

Answer: 21

54.9 Ordering lengths

Length tells how long something is. Standard units such as centimetres and metres make measurements comparable. Use objects, drawings, number lines, tables, or number sentences when useful.

10 Worked Examples with Answers

Worked Example 1

Problem: Use 8 and 5 to make a simple example about Ordering lengths.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Ordering lengths.

Worked Example 2

Problem: Use 12 and 20 to make a simple example about Ordering lengths.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Ordering lengths.

Worked Example 3

Problem: Use 16 and 15 to make a simple example about Ordering lengths.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Ordering lengths.

Worked Example 4

Problem: Use 11 and 2 to make a simple example about Ordering lengths.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Ordering lengths.

Worked Example 5

Problem: Use 19 and 10 to make a simple example about Ordering lengths.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Ordering lengths.

Worked Example 6

Problem: Use 6 and 14 to make a simple example about Ordering lengths.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Ordering lengths.

Worked Example 7

Problem: Use 17 and 14 to make a simple example about Ordering lengths.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Ordering lengths.

Worked Example 8

Problem: Use 14 and 10 to make a simple example about Ordering lengths.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Ordering lengths.

Worked Example 9

Problem: Use 8 and 10 to make a simple example about Ordering lengths.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Ordering lengths.

Worked Example 10

Problem: Use 7 and 8 to make a simple example about Ordering lengths.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Ordering lengths.

54.10 Reasonable estimates

Estimation gives a nearby amount. The nearest ten is the multiple of ten closest to the number. Use objects, drawings, number lines, tables, or number sentences when useful.

10 Worked Examples with Answers

Worked Example 1

Problem: Which ten is closer to 13: 10 or 20?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 10

Worked Example 2

Problem: Which ten is closer to 19: 10 or 20?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 20

Worked Example 3

Problem: Which ten is closer to 56: 50 or 60?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 60

Worked Example 4

Problem: Which ten is closer to 24: 20 or 30?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 20

Worked Example 5

Problem: Which ten is closer to 89: 80 or 90?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 90

Worked Example 6

Problem: Which ten is closer to 54: 50 or 60?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 50

Worked Example 7

Problem: Which ten is closer to 60: 60 or 70?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 60

Worked Example 8

Problem: Which ten is closer to 13: 10 or 20?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 10

Worked Example 9

Problem: Which ten is closer to 24: 20 or 30?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 20

Worked Example 10

Problem: Which ten is closer to 76: 70 or 80?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 80

54.11 Improving an estimate

Estimation gives a nearby amount. The nearest ten is the multiple of ten closest to the number. Use objects, drawings, number lines, tables, or number sentences when useful.

10 Worked Examples with Answers

Worked Example 1

Problem: Which ten is closer to 34: 30 or 40?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 30

Worked Example 2

Problem: Which ten is closer to 35: 30 or 40?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 40

Worked Example 3

Problem: Which ten is closer to 56: 50 or 60?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 60

Worked Example 4

Problem: Which ten is closer to 33: 30 or 40?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 30

Worked Example 5

Problem: Which ten is closer to 32: 30 or 40?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 30

Worked Example 6

Problem: Which ten is closer to 91: 90 or 100?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 90

Worked Example 7

Problem: Which ten is closer to 94: 90 or 100?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 90

Worked Example 8

Problem: Which ten is closer to 67: 60 or 70?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 70

Worked Example 9

Problem: Which ten is closer to 36: 30 or 40?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 40

Worked Example 10

Problem: Which ten is closer to 49: 40 or 50?

  1. Find the distance to each ten.
  2. Choose the closer one.

Very beginner explanation: Nearest-ten thinking uses multiples of ten as benchmarks.

Answer: 50

54.12 Real-life length problems

Length tells how long something is. Standard units such as centimetres and metres make measurements comparable. Use objects, drawings, number lines, tables, or number sentences when useful.

10 Worked Examples with Answers

Worked Example 1

Problem: Use 15 and 15 to make a simple example about Real-life length problems.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Real-life length problems.

Worked Example 2

Problem: Use 9 and 2 to make a simple example about Real-life length problems.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Real-life length problems.

Worked Example 3

Problem: Use 14 and 2 to make a simple example about Real-life length problems.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Real-life length problems.

Worked Example 4

Problem: Use 4 and 5 to make a simple example about Real-life length problems.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Real-life length problems.

Worked Example 5

Problem: Use 18 and 15 to make a simple example about Real-life length problems.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Real-life length problems.

Worked Example 6

Problem: Use 10 and 12 to make a simple example about Real-life length problems.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Real-life length problems.

Worked Example 7

Problem: Use 6 and 17 to make a simple example about Real-life length problems.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Real-life length problems.

Worked Example 8

Problem: Use 18 and 8 to make a simple example about Real-life length problems.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Real-life length problems.

Worked Example 9

Problem: Use 4 and 14 to make a simple example about Real-life length problems.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Real-life length problems.

Worked Example 10

Problem: Use 12 and 10 to make a simple example about Real-life length problems.

  1. Recall the topic meaning.
  2. Use objects, a drawing, or a number sentence.
  3. Check that the example matches the idea.

Very beginner explanation: Simple models make Grade 2 ideas easier to understand.

Answer: A correct Grade 2 example of Real-life length problems.

30 Review Questions and Answers

Q1. What should a Grade 2 learner understand about Estimating in centimetres?

Answer: Length tells how long something is. Standard units such as centimetres and metres make measurements comparable.

Q2. What should a Grade 2 learner understand about Estimating in metres?

Answer: Length tells how long something is. Standard units such as centimetres and metres make measurements comparable.

Q3. What should a Grade 2 learner understand about Using benchmarks?

Answer: Using benchmarks is a Grade 2 math idea best learned with simple numbers, objects, drawings, and clear words.

Q4. What should a Grade 2 learner understand about Longer and shorter?

Answer: Longer and shorter is a Grade 2 math idea best learned with simple numbers, objects, drawings, and clear words.

Q5. What should a Grade 2 learner understand about Same length?

Answer: Length tells how long something is. Standard units such as centimetres and metres make measurements comparable.

Q6. What should a Grade 2 learner understand about Comparing estimates and measurements?

Answer: Estimation gives a nearby amount. The nearest ten is the multiple of ten closest to the number.

Q7. What should a Grade 2 learner understand about Choosing a useful benchmark?

Answer: Choosing a useful benchmark is a Grade 2 math idea best learned with simple numbers, objects, drawings, and clear words.

Q8. What should a Grade 2 learner understand about Finding a difference in length?

Answer: Subtraction can mean taking away, finding a difference, or finding a missing part. Addition can check the answer.

Q9. What should a Grade 2 learner understand about Ordering lengths?

Answer: Length tells how long something is. Standard units such as centimetres and metres make measurements comparable.

Q10. What should a Grade 2 learner understand about Reasonable estimates?

Answer: Estimation gives a nearby amount. The nearest ten is the multiple of ten closest to the number.

Q11. What should a Grade 2 learner understand about Improving an estimate?

Answer: Estimation gives a nearby amount. The nearest ten is the multiple of ten closest to the number.

Q12. What should a Grade 2 learner understand about Real-life length problems?

Answer: Length tells how long something is. Standard units such as centimetres and metres make measurements comparable.

Q13. What should a Grade 2 learner understand about Estimating in centimetres?

Answer: Length tells how long something is. Standard units such as centimetres and metres make measurements comparable.

Q14. What should a Grade 2 learner understand about Estimating in metres?

Answer: Length tells how long something is. Standard units such as centimetres and metres make measurements comparable.

Q15. What should a Grade 2 learner understand about Using benchmarks?

Answer: Using benchmarks is a Grade 2 math idea best learned with simple numbers, objects, drawings, and clear words.

Q16. What should a Grade 2 learner understand about Longer and shorter?

Answer: Longer and shorter is a Grade 2 math idea best learned with simple numbers, objects, drawings, and clear words.

Q17. What should a Grade 2 learner understand about Same length?

Answer: Length tells how long something is. Standard units such as centimetres and metres make measurements comparable.

Q18. What should a Grade 2 learner understand about Comparing estimates and measurements?

Answer: Estimation gives a nearby amount. The nearest ten is the multiple of ten closest to the number.

Q19. What should a Grade 2 learner understand about Choosing a useful benchmark?

Answer: Choosing a useful benchmark is a Grade 2 math idea best learned with simple numbers, objects, drawings, and clear words.

Q20. What should a Grade 2 learner understand about Finding a difference in length?

Answer: Subtraction can mean taking away, finding a difference, or finding a missing part. Addition can check the answer.

Q21. What should a Grade 2 learner understand about Ordering lengths?

Answer: Length tells how long something is. Standard units such as centimetres and metres make measurements comparable.

Q22. What should a Grade 2 learner understand about Reasonable estimates?

Answer: Estimation gives a nearby amount. The nearest ten is the multiple of ten closest to the number.

Q23. What should a Grade 2 learner understand about Improving an estimate?

Answer: Estimation gives a nearby amount. The nearest ten is the multiple of ten closest to the number.

Q24. What should a Grade 2 learner understand about Real-life length problems?

Answer: Length tells how long something is. Standard units such as centimetres and metres make measurements comparable.

Q25. What should a Grade 2 learner understand about Estimating in centimetres?

Answer: Length tells how long something is. Standard units such as centimetres and metres make measurements comparable.

Q26. What should a Grade 2 learner understand about Estimating in metres?

Answer: Length tells how long something is. Standard units such as centimetres and metres make measurements comparable.

Q27. What should a Grade 2 learner understand about Using benchmarks?

Answer: Using benchmarks is a Grade 2 math idea best learned with simple numbers, objects, drawings, and clear words.

Q28. What should a Grade 2 learner understand about Longer and shorter?

Answer: Longer and shorter is a Grade 2 math idea best learned with simple numbers, objects, drawings, and clear words.

Q29. What should a Grade 2 learner understand about Same length?

Answer: Length tells how long something is. Standard units such as centimetres and metres make measurements comparable.

Q30. What should a Grade 2 learner understand about Comparing estimates and measurements?

Answer: Estimation gives a nearby amount. The nearest ten is the multiple of ten closest to the number.