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Chapter 23: Subtracting Two-Digit Numbers With Regrouping

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 Subtracting Two-Digit Numbers With Regrouping with simple explanations, visual thinking, worked examples, practice, and review.

23.1 Trading one ten for ten ones

Place value tells how much a digit is worth because of its position in a number. Use objects, drawings, number lines, tables, or number sentences when useful.

10 Worked Examples with Answers

Worked Example 1

Problem: How many hundreds, tens, and ones are in 181?

  1. Read the hundreds digit.
  2. Read the tens digit.
  3. Read the ones digit.

Very beginner explanation: Position tells place value.

Answer: 1 hundred, 8 tens, 1 ones

Worked Example 2

Problem: How many hundreds, tens, and ones are in 103?

  1. Read the hundreds digit.
  2. Read the tens digit.
  3. Read the ones digit.

Very beginner explanation: Position tells place value.

Answer: 1 hundred, 0 tens, 3 ones

Worked Example 3

Problem: How many hundreds, tens, and ones are in 171?

  1. Read the hundreds digit.
  2. Read the tens digit.
  3. Read the ones digit.

Very beginner explanation: Position tells place value.

Answer: 1 hundred, 7 tens, 1 ones

Worked Example 4

Problem: How many hundreds, tens, and ones are in 141?

  1. Read the hundreds digit.
  2. Read the tens digit.
  3. Read the ones digit.

Very beginner explanation: Position tells place value.

Answer: 1 hundred, 4 tens, 1 ones

Worked Example 5

Problem: How many hundreds, tens, and ones are in 159?

  1. Read the hundreds digit.
  2. Read the tens digit.
  3. Read the ones digit.

Very beginner explanation: Position tells place value.

Answer: 1 hundred, 5 tens, 9 ones

Worked Example 6

Problem: How many hundreds, tens, and ones are in 189?

  1. Read the hundreds digit.
  2. Read the tens digit.
  3. Read the ones digit.

Very beginner explanation: Position tells place value.

Answer: 1 hundred, 8 tens, 9 ones

Worked Example 7

Problem: How many hundreds, tens, and ones are in 190?

  1. Read the hundreds digit.
  2. Read the tens digit.
  3. Read the ones digit.

Very beginner explanation: Position tells place value.

Answer: 1 hundred, 9 tens, 0 ones

Worked Example 8

Problem: How many hundreds, tens, and ones are in 102?

  1. Read the hundreds digit.
  2. Read the tens digit.
  3. Read the ones digit.

Very beginner explanation: Position tells place value.

Answer: 1 hundred, 0 tens, 2 ones

Worked Example 9

Problem: How many hundreds, tens, and ones are in 152?

  1. Read the hundreds digit.
  2. Read the tens digit.
  3. Read the ones digit.

Very beginner explanation: Position tells place value.

Answer: 1 hundred, 5 tens, 2 ones

Worked Example 10

Problem: How many hundreds, tens, and ones are in 199?

  1. Read the hundreds digit.
  2. Read the tens digit.
  3. Read the ones digit.

Very beginner explanation: Position tells place value.

Answer: 1 hundred, 9 tens, 9 ones

23.2 Place-value models for regrouping

Place-value models for regrouping 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 13 to make a simple example about Place-value models for regrouping.

  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 Place-value models for regrouping.

Worked Example 2

Problem: Use 10 and 9 to make a simple example about Place-value models for regrouping.

  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 Place-value models for regrouping.

Worked Example 3

Problem: Use 11 and 20 to make a simple example about Place-value models for regrouping.

  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 Place-value models for regrouping.

Worked Example 4

Problem: Use 13 and 4 to make a simple example about Place-value models for regrouping.

  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 Place-value models for regrouping.

Worked Example 5

Problem: Use 10 and 5 to make a simple example about Place-value models for regrouping.

  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 Place-value models for regrouping.

Worked Example 6

Problem: Use 20 and 3 to make a simple example about Place-value models for regrouping.

  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 Place-value models for regrouping.

Worked Example 7

Problem: Use 14 and 5 to make a simple example about Place-value models for regrouping.

  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 Place-value models for regrouping.

Worked Example 8

Problem: Use 11 and 18 to make a simple example about Place-value models for regrouping.

  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 Place-value models for regrouping.

Worked Example 9

Problem: Use 4 and 13 to make a simple example about Place-value models for regrouping.

  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 Place-value models for regrouping.

Worked Example 10

Problem: Use 11 and 8 to make a simple example about Place-value models for regrouping.

  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 Place-value models for regrouping.

23.3 Open number-line strategies

Open number-line strategies 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 5 and 15 to make a simple example about Open number-line strategies.

  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 Open number-line strategies.

Worked Example 2

Problem: Use 12 and 6 to make a simple example about Open number-line strategies.

  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 Open number-line strategies.

Worked Example 3

Problem: Use 16 and 2 to make a simple example about Open number-line strategies.

  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 Open number-line strategies.

Worked Example 4

Problem: Use 16 and 16 to make a simple example about Open number-line strategies.

  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 Open number-line strategies.

Worked Example 5

Problem: Use 14 and 6 to make a simple example about Open number-line strategies.

  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 Open number-line strategies.

Worked Example 6

Problem: Use 14 and 20 to make a simple example about Open number-line strategies.

  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 Open number-line strategies.

Worked Example 7

Problem: Use 1 and 9 to make a simple example about Open number-line strategies.

  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 Open number-line strategies.

Worked Example 8

Problem: Use 16 and 15 to make a simple example about Open number-line strategies.

  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 Open number-line strategies.

Worked Example 9

Problem: Use 20 and 11 to make a simple example about Open number-line strategies.

  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 Open number-line strategies.

Worked Example 10

Problem: Use 3 and 12 to make a simple example about Open number-line strategies.

  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 Open number-line strategies.

23.4 Breaking apart numbers

Breaking apart numbers 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 4 to make a simple example about Breaking apart numbers.

  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 Breaking apart numbers.

Worked Example 2

Problem: Use 20 and 12 to make a simple example about Breaking apart numbers.

  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 Breaking apart numbers.

Worked Example 3

Problem: Use 16 and 17 to make a simple example about Breaking apart numbers.

  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 Breaking apart numbers.

Worked Example 4

Problem: Use 13 and 15 to make a simple example about Breaking apart numbers.

  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 Breaking apart numbers.

Worked Example 5

Problem: Use 14 and 15 to make a simple example about Breaking apart numbers.

  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 Breaking apart numbers.

Worked Example 6

Problem: Use 10 and 7 to make a simple example about Breaking apart numbers.

  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 Breaking apart numbers.

Worked Example 7

Problem: Use 4 and 4 to make a simple example about Breaking apart numbers.

  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 Breaking apart numbers.

Worked Example 8

Problem: Use 11 and 5 to make a simple example about Breaking apart numbers.

  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 Breaking apart numbers.

Worked Example 9

Problem: Use 4 and 1 to make a simple example about Breaking apart numbers.

  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 Breaking apart numbers.

Worked Example 10

Problem: Use 4 and 1 to make a simple example about Breaking apart numbers.

  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 Breaking apart numbers.

23.5 Vertical subtraction with regrouping

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 145 − 137.

  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: 8

Worked Example 2

Problem: Find 79 − 19.

  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: 60

Worked Example 3

Problem: Find 89 − 25.

  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: 64

Worked Example 4

Problem: Find 22 − 11.

  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: 11

Worked Example 5

Problem: Find 89 − 80.

  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: 9

Worked Example 6

Problem: Find 44 − 10.

  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: 34

Worked Example 7

Problem: Find 128 − 40.

  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 8

Problem: Find 119 − 41.

  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: 78

Worked Example 9

Problem: Find 139 − 119.

  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: 20

Worked Example 10

Problem: Find 68 − 15.

  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: 53

23.6 Subtracting across a ten

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 145 − 91.

  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 2

Problem: Find 80 − 42.

  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: 38

Worked Example 3

Problem: Find 29 − 19.

  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: 10

Worked Example 4

Problem: Find 54 − 38.

  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: 16

Worked Example 5

Problem: Find 113 − 79.

  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: 34

Worked Example 6

Problem: Find 125 − 52.

  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: 73

Worked Example 7

Problem: Find 96 − 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: 95

Worked Example 8

Problem: Find 110 − 31.

  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: 79

Worked Example 9

Problem: Find 142 − 127.

  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 10

Problem: Find 23 − 6.

  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: 17

23.7 Finding a difference near a benchmark

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 118 − 95.

  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: 23

Worked Example 2

Problem: Find 72 − 71.

  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: 1

Worked Example 3

Problem: Find 74 − 70.

  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: 4

Worked Example 4

Problem: Find 120 − 99.

  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

Worked Example 5

Problem: Find 41 − 3.

  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: 38

Worked Example 6

Problem: Find 29 − 17.

  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: 12

Worked Example 7

Problem: Find 121 − 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: 72

Worked Example 8

Problem: Find 72 − 56.

  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: 16

Worked Example 9

Problem: Find 60 − 58.

  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: 2

Worked Example 10

Problem: Find 54 − 34.

  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: 20

23.8 Estimating a difference

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 45 − 20.

  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 2

Problem: Find 109 − 109.

  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: 0

Worked Example 3

Problem: Find 31 − 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: 4

Worked Example 4

Problem: Find 64 − 60.

  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: 4

Worked Example 5

Problem: Find 133 − 7.

  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: 126

Worked Example 6

Problem: Find 69 − 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: 68

Worked Example 7

Problem: Find 117 − 69.

  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 32 − 29.

  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: 3

Worked Example 9

Problem: Find 141 − 133.

  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: 8

Worked Example 10

Problem: Find 132 − 16.

  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: 116

23.9 Word problems with regrouping

Word problems with regrouping 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 15 and 16 to make a simple example about Word problems with regrouping.

  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 Word problems with regrouping.

Worked Example 2

Problem: Use 2 and 9 to make a simple example about Word problems with regrouping.

  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 Word problems with regrouping.

Worked Example 3

Problem: Use 11 and 10 to make a simple example about Word problems with regrouping.

  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 Word problems with regrouping.

Worked Example 4

Problem: Use 10 and 4 to make a simple example about Word problems with regrouping.

  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 Word problems with regrouping.

Worked Example 5

Problem: Use 7 and 1 to make a simple example about Word problems with regrouping.

  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 Word problems with regrouping.

Worked Example 6

Problem: Use 9 and 18 to make a simple example about Word problems with regrouping.

  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 Word problems with regrouping.

Worked Example 7

Problem: Use 3 and 18 to make a simple example about Word problems with regrouping.

  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 Word problems with regrouping.

Worked Example 8

Problem: Use 8 and 6 to make a simple example about Word problems with regrouping.

  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 Word problems with regrouping.

Worked Example 9

Problem: Use 11 and 18 to make a simple example about Word problems with regrouping.

  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 Word problems with regrouping.

Worked Example 10

Problem: Use 4 and 12 to make a simple example about Word problems with regrouping.

  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 Word problems with regrouping.

23.10 Checking with addition

Addition combines quantities. Counting on, making ten, drawings, and place value can help. Use objects, drawings, number lines, tables, or number sentences when useful.

10 Worked Examples with Answers

Worked Example 1

Problem: Find 54 + 51.

  1. Start with the larger number.
  2. Add tens or make a ten if helpful.
  3. Add the remaining ones.

Very beginner explanation: Addition combines quantities.

Answer: 105

Worked Example 2

Problem: Find 45 + 58.

  1. Start with the larger number.
  2. Add tens or make a ten if helpful.
  3. Add the remaining ones.

Very beginner explanation: Addition combines quantities.

Answer: 103

Worked Example 3

Problem: Find 2 + 60.

  1. Start with the larger number.
  2. Add tens or make a ten if helpful.
  3. Add the remaining ones.

Very beginner explanation: Addition combines quantities.

Answer: 62

Worked Example 4

Problem: Find 36 + 39.

  1. Start with the larger number.
  2. Add tens or make a ten if helpful.
  3. Add the remaining ones.

Very beginner explanation: Addition combines quantities.

Answer: 75

Worked Example 5

Problem: Find 13 + 6.

  1. Start with the larger number.
  2. Add tens or make a ten if helpful.
  3. Add the remaining ones.

Very beginner explanation: Addition combines quantities.

Answer: 19

Worked Example 6

Problem: Find 10 + 22.

  1. Start with the larger number.
  2. Add tens or make a ten if helpful.
  3. Add the remaining ones.

Very beginner explanation: Addition combines quantities.

Answer: 32

Worked Example 7

Problem: Find 7 + 2.

  1. Start with the larger number.
  2. Add tens or make a ten if helpful.
  3. Add the remaining ones.

Very beginner explanation: Addition combines quantities.

Answer: 9

Worked Example 8

Problem: Find 18 + 51.

  1. Start with the larger number.
  2. Add tens or make a ten if helpful.
  3. Add the remaining ones.

Very beginner explanation: Addition combines quantities.

Answer: 69

Worked Example 9

Problem: Find 18 + 13.

  1. Start with the larger number.
  2. Add tens or make a ten if helpful.
  3. Add the remaining ones.

Very beginner explanation: Addition combines quantities.

Answer: 31

Worked Example 10

Problem: Find 10 + 12.

  1. Start with the larger number.
  2. Add tens or make a ten if helpful.
  3. Add the remaining ones.

Very beginner explanation: Addition combines quantities.

Answer: 22

23.11 Explaining regrouping

Explaining regrouping 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 14 and 2 to make a simple example about Explaining regrouping.

  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 Explaining regrouping.

Worked Example 2

Problem: Use 15 and 2 to make a simple example about Explaining regrouping.

  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 Explaining regrouping.

Worked Example 3

Problem: Use 20 and 13 to make a simple example about Explaining regrouping.

  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 Explaining regrouping.

Worked Example 4

Problem: Use 2 and 1 to make a simple example about Explaining regrouping.

  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 Explaining regrouping.

Worked Example 5

Problem: Use 14 and 13 to make a simple example about Explaining regrouping.

  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 Explaining regrouping.

Worked Example 6

Problem: Use 10 and 8 to make a simple example about Explaining regrouping.

  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 Explaining regrouping.

Worked Example 7

Problem: Use 20 and 18 to make a simple example about Explaining regrouping.

  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 Explaining regrouping.

Worked Example 8

Problem: Use 7 and 13 to make a simple example about Explaining regrouping.

  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 Explaining regrouping.

Worked Example 9

Problem: Use 5 and 20 to make a simple example about Explaining regrouping.

  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 Explaining regrouping.

Worked Example 10

Problem: Use 2 and 1 to make a simple example about Explaining regrouping.

  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 Explaining regrouping.

23.12 Mixed regrouping practice

Mixed regrouping practice 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 15 and 14 to make a simple example about Mixed regrouping practice.

  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 Mixed regrouping practice.

Worked Example 2

Problem: Use 14 and 10 to make a simple example about Mixed regrouping practice.

  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 Mixed regrouping practice.

Worked Example 3

Problem: Use 8 and 11 to make a simple example about Mixed regrouping practice.

  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 Mixed regrouping practice.

Worked Example 4

Problem: Use 12 and 19 to make a simple example about Mixed regrouping practice.

  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 Mixed regrouping practice.

Worked Example 5

Problem: Use 2 and 3 to make a simple example about Mixed regrouping practice.

  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 Mixed regrouping practice.

Worked Example 6

Problem: Use 19 and 20 to make a simple example about Mixed regrouping practice.

  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 Mixed regrouping practice.

Worked Example 7

Problem: Use 9 and 14 to make a simple example about Mixed regrouping practice.

  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 Mixed regrouping practice.

Worked Example 8

Problem: Use 18 and 10 to make a simple example about Mixed regrouping practice.

  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 Mixed regrouping practice.

Worked Example 9

Problem: Use 2 and 1 to make a simple example about Mixed regrouping practice.

  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 Mixed regrouping practice.

Worked Example 10

Problem: Use 11 and 14 to make a simple example about Mixed regrouping practice.

  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 Mixed regrouping practice.

30 Review Questions and Answers

Q1. What should a Grade 2 learner understand about Trading one ten for ten ones?

Answer: Place value tells how much a digit is worth because of its position in a number.

Q2. What should a Grade 2 learner understand about Place-value models for regrouping?

Answer: Place-value models for regrouping is a Grade 2 math idea best learned with simple numbers, objects, drawings, and clear words.

Q3. What should a Grade 2 learner understand about Open number-line strategies?

Answer: Open number-line strategies 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 Breaking apart numbers?

Answer: Breaking apart numbers 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 Vertical subtraction with regrouping?

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

Q6. What should a Grade 2 learner understand about Subtracting across a ten?

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

Q7. What should a Grade 2 learner understand about Finding a difference near a benchmark?

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

Q8. What should a Grade 2 learner understand about Estimating a difference?

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 Word problems with regrouping?

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

Q10. What should a Grade 2 learner understand about Checking with addition?

Answer: Addition combines quantities. Counting on, making ten, drawings, and place value can help.

Q11. What should a Grade 2 learner understand about Explaining regrouping?

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

Q12. What should a Grade 2 learner understand about Mixed regrouping practice?

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

Q13. What should a Grade 2 learner understand about Trading one ten for ten ones?

Answer: Place value tells how much a digit is worth because of its position in a number.

Q14. What should a Grade 2 learner understand about Place-value models for regrouping?

Answer: Place-value models for regrouping is a Grade 2 math idea best learned with simple numbers, objects, drawings, and clear words.

Q15. What should a Grade 2 learner understand about Open number-line strategies?

Answer: Open number-line strategies 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 Breaking apart numbers?

Answer: Breaking apart numbers 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 Vertical subtraction with regrouping?

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

Q18. What should a Grade 2 learner understand about Subtracting across a ten?

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

Q19. What should a Grade 2 learner understand about Finding a difference near a benchmark?

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

Q20. What should a Grade 2 learner understand about Estimating a difference?

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 Word problems with regrouping?

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

Q22. What should a Grade 2 learner understand about Checking with addition?

Answer: Addition combines quantities. Counting on, making ten, drawings, and place value can help.

Q23. What should a Grade 2 learner understand about Explaining regrouping?

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

Q24. What should a Grade 2 learner understand about Mixed regrouping practice?

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

Q25. What should a Grade 2 learner understand about Trading one ten for ten ones?

Answer: Place value tells how much a digit is worth because of its position in a number.

Q26. What should a Grade 2 learner understand about Place-value models for regrouping?

Answer: Place-value models for regrouping is a Grade 2 math idea best learned with simple numbers, objects, drawings, and clear words.

Q27. What should a Grade 2 learner understand about Open number-line strategies?

Answer: Open number-line strategies 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 Breaking apart numbers?

Answer: Breaking apart numbers 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 Vertical subtraction with regrouping?

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

Q30. What should a Grade 2 learner understand about Subtracting across a ten?

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