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Chapter 21: Subtraction Facts Within 20

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 Subtraction Facts Within 20 with simple explanations, visual thinking, worked examples, practice, and review.

21.1 Facts subtracting 0

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 81 − 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: 39

Worked Example 2

Problem: Find 95 − 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: 55

Worked Example 3

Problem: Find 114 − 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: 58

Worked Example 4

Problem: Find 144 − 45.

  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: 99

Worked Example 5

Problem: Find 86 − 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: 85

Worked Example 6

Problem: Find 80 − 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: 32

Worked Example 7

Problem: Find 146 − 53.

  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: 93

Worked Example 8

Problem: Find 107 − 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: 67

Worked Example 9

Problem: Find 137 − 86.

  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: 51

Worked Example 10

Problem: Find 143 − 55.

  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

21.2 Facts subtracting 1

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 28 − 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: 27

Worked Example 2

Problem: Find 27 − 24.

  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 3

Problem: Find 74 − 26.

  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 4

Problem: Find 82 − 61.

  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 21 − 14.

  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 20 − 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: 19

Worked Example 7

Problem: Find 90 − 57.

  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: 33

Worked Example 8

Problem: Find 53 − 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: 12

Worked Example 9

Problem: Find 96 − 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: 23

Worked Example 10

Problem: Find 43 − 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: 42

21.3 Facts from 10

Facts from 10 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 12 and 4 to make a simple example about Facts from 10.

  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 Facts from 10.

Worked Example 2

Problem: Use 18 and 9 to make a simple example about Facts from 10.

  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 Facts from 10.

Worked Example 3

Problem: Use 19 and 16 to make a simple example about Facts from 10.

  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 Facts from 10.

Worked Example 4

Problem: Use 6 and 16 to make a simple example about Facts from 10.

  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 Facts from 10.

Worked Example 5

Problem: Use 3 and 16 to make a simple example about Facts from 10.

  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 Facts from 10.

Worked Example 6

Problem: Use 16 and 12 to make a simple example about Facts from 10.

  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 Facts from 10.

Worked Example 7

Problem: Use 13 and 10 to make a simple example about Facts from 10.

  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 Facts from 10.

Worked Example 8

Problem: Use 2 and 4 to make a simple example about Facts from 10.

  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 Facts from 10.

Worked Example 9

Problem: Use 19 and 6 to make a simple example about Facts from 10.

  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 Facts from 10.

Worked Example 10

Problem: Use 5 and 11 to make a simple example about Facts from 10.

  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 Facts from 10.

21.4 Facts from doubles

Facts from doubles 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 2 and 6 to make a simple example about Facts from doubles.

  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 Facts from doubles.

Worked Example 2

Problem: Use 4 and 1 to make a simple example about Facts from doubles.

  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 Facts from doubles.

Worked Example 3

Problem: Use 4 and 1 to make a simple example about Facts from doubles.

  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 Facts from doubles.

Worked Example 4

Problem: Use 10 and 10 to make a simple example about Facts from doubles.

  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 Facts from doubles.

Worked Example 5

Problem: Use 12 and 17 to make a simple example about Facts from doubles.

  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 Facts from doubles.

Worked Example 6

Problem: Use 15 and 10 to make a simple example about Facts from doubles.

  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 Facts from doubles.

Worked Example 7

Problem: Use 14 and 4 to make a simple example about Facts from doubles.

  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 Facts from doubles.

Worked Example 8

Problem: Use 8 and 11 to make a simple example about Facts from doubles.

  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 Facts from doubles.

Worked Example 9

Problem: Use 16 and 2 to make a simple example about Facts from doubles.

  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 Facts from doubles.

Worked Example 10

Problem: Use 20 and 7 to make a simple example about Facts from doubles.

  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 Facts from doubles.

21.5 Using addition facts

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 60 + 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: 62

Worked Example 2

Problem: Find 4 + 45.

  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: 49

Worked Example 3

Problem: Find 38 + 15.

  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: 53

Worked Example 4

Problem: Find 59 + 32.

  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: 91

Worked Example 5

Problem: Find 5 + 44.

  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: 49

Worked Example 6

Problem: Find 4 + 31.

  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: 35

Worked Example 7

Problem: Find 50 + 20.

  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: 70

Worked Example 8

Problem: Find 19 + 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: 58

Worked Example 9

Problem: Find 44 + 50.

  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: 94

Worked Example 10

Problem: Find 17 + 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: 56

21.6 Counting back

Counting patterns organize numbers and help with addition, subtraction, and number relationships. Use objects, drawings, number lines, tables, or number sentences when useful.

10 Worked Examples with Answers

Worked Example 1

Problem: Continue 1, 3, 5, ...

  1. The rule is add 2.
  2. Use the same rule again.

Very beginner explanation: Counting patterns use a consistent step.

Answer: 7, 9

Worked Example 2

Problem: Continue 40, 45, 50, ...

  1. The rule is add 5.
  2. Use the same rule again.

Very beginner explanation: Counting patterns use a consistent step.

Answer: 55, 60

Worked Example 3

Problem: Continue 32, 34, 36, ...

  1. The rule is add 2.
  2. Use the same rule again.

Very beginner explanation: Counting patterns use a consistent step.

Answer: 38, 40

Worked Example 4

Problem: Continue 16, 17, 18, ...

  1. The rule is add 1.
  2. Use the same rule again.

Very beginner explanation: Counting patterns use a consistent step.

Answer: 19, 20

Worked Example 5

Problem: Continue 34, 35, 36, ...

  1. The rule is add 1.
  2. Use the same rule again.

Very beginner explanation: Counting patterns use a consistent step.

Answer: 37, 38

Worked Example 6

Problem: Continue 20, 25, 30, ...

  1. The rule is add 5.
  2. Use the same rule again.

Very beginner explanation: Counting patterns use a consistent step.

Answer: 35, 40

Worked Example 7

Problem: Continue 20, 30, 40, ...

  1. The rule is add 10.
  2. Use the same rule again.

Very beginner explanation: Counting patterns use a consistent step.

Answer: 50, 60

Worked Example 8

Problem: Continue 24, 29, 34, ...

  1. The rule is add 5.
  2. Use the same rule again.

Very beginner explanation: Counting patterns use a consistent step.

Answer: 39, 44

Worked Example 9

Problem: Continue 18, 19, 20, ...

  1. The rule is add 1.
  2. Use the same rule again.

Very beginner explanation: Counting patterns use a consistent step.

Answer: 21, 22

Worked Example 10

Problem: Continue 30, 40, 50, ...

  1. The rule is add 10.
  2. Use the same rule again.

Very beginner explanation: Counting patterns use a consistent step.

Answer: 60, 70

21.7 Counting up

Counting patterns organize numbers and help with addition, subtraction, and number relationships. Use objects, drawings, number lines, tables, or number sentences when useful.

10 Worked Examples with Answers

Worked Example 1

Problem: Continue 27, 28, 29, ...

  1. The rule is add 1.
  2. Use the same rule again.

Very beginner explanation: Counting patterns use a consistent step.

Answer: 30, 31

Worked Example 2

Problem: Continue 40, 50, 60, ...

  1. The rule is add 10.
  2. Use the same rule again.

Very beginner explanation: Counting patterns use a consistent step.

Answer: 70, 80

Worked Example 3

Problem: Continue 11, 12, 13, ...

  1. The rule is add 1.
  2. Use the same rule again.

Very beginner explanation: Counting patterns use a consistent step.

Answer: 14, 15

Worked Example 4

Problem: Continue 3, 5, 7, ...

  1. The rule is add 2.
  2. Use the same rule again.

Very beginner explanation: Counting patterns use a consistent step.

Answer: 9, 11

Worked Example 5

Problem: Continue 31, 36, 41, ...

  1. The rule is add 5.
  2. Use the same rule again.

Very beginner explanation: Counting patterns use a consistent step.

Answer: 46, 51

Worked Example 6

Problem: Continue 5, 6, 7, ...

  1. The rule is add 1.
  2. Use the same rule again.

Very beginner explanation: Counting patterns use a consistent step.

Answer: 8, 9

Worked Example 7

Problem: Continue 4, 5, 6, ...

  1. The rule is add 1.
  2. Use the same rule again.

Very beginner explanation: Counting patterns use a consistent step.

Answer: 7, 8

Worked Example 8

Problem: Continue 16, 26, 36, ...

  1. The rule is add 10.
  2. Use the same rule again.

Very beginner explanation: Counting patterns use a consistent step.

Answer: 46, 56

Worked Example 9

Problem: Continue 5, 10, 15, ...

  1. The rule is add 5.
  2. Use the same rule again.

Very beginner explanation: Counting patterns use a consistent step.

Answer: 20, 25

Worked Example 10

Problem: Continue 16, 21, 26, ...

  1. The rule is add 5.
  2. Use the same rule again.

Very beginner explanation: Counting patterns use a consistent step.

Answer: 31, 36

21.8 Subtracting 5

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 23 − 12.

  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 2

Problem: Find 144 − 105.

  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: 39

Worked Example 3

Problem: Find 49 − 44.

  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: 5

Worked Example 4

Problem: Find 79 − 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: 52

Worked Example 5

Problem: Find 64 − 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: 34

Worked Example 6

Problem: Find 80 − 53.

  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: 27

Worked Example 7

Problem: Find 59 − 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: 36

Worked Example 8

Problem: Find 40 − 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: 11

Worked Example 9

Problem: Find 126 − 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: 120

Worked Example 10

Problem: Find 76 − 4.

  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

21.9 Subtracting 10

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 113 − 57.

  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: 56

Worked Example 2

Problem: Find 149 − 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: 78

Worked Example 3

Problem: Find 139 − 51.

  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 4

Problem: Find 22 − 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: 6

Worked Example 5

Problem: Find 37 − 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: 8

Worked Example 6

Problem: Find 90 − 64.

  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 7

Problem: Find 75 − 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: 37

Worked Example 8

Problem: Find 82 − 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: 42

Worked Example 9

Problem: Find 65 − 26.

  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: 39

Worked Example 10

Problem: Find 94 − 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: 45

21.10 Fact families

Fact families 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 10 to make a simple example about Fact families.

  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 Fact families.

Worked Example 2

Problem: Use 3 and 8 to make a simple example about Fact families.

  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 Fact families.

Worked Example 3

Problem: Use 16 and 14 to make a simple example about Fact families.

  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 Fact families.

Worked Example 4

Problem: Use 11 and 16 to make a simple example about Fact families.

  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 Fact families.

Worked Example 5

Problem: Use 4 and 4 to make a simple example about Fact families.

  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 Fact families.

Worked Example 6

Problem: Use 20 and 18 to make a simple example about Fact families.

  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 Fact families.

Worked Example 7

Problem: Use 13 and 2 to make a simple example about Fact families.

  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 Fact families.

Worked Example 8

Problem: Use 14 and 1 to make a simple example about Fact families.

  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 Fact families.

Worked Example 9

Problem: Use 18 and 9 to make a simple example about Fact families.

  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 Fact families.

Worked Example 10

Problem: Use 10 and 20 to make a simple example about Fact families.

  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 Fact families.

21.11 Missing-number subtraction

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 79 − 72.

  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 2

Problem: Find 118 − 116.

  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 3

Problem: Find 120 − 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: 41

Worked Example 4

Problem: Find 69 − 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: 17

Worked Example 5

Problem: Find 88 − 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: 81

Worked Example 6

Problem: Find 47 − 24.

  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 7

Problem: Find 131 − 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: 100

Worked Example 8

Problem: Find 41 − 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: 3

Worked Example 9

Problem: Find 49 − 24.

  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 10

Problem: Find 98 − 63.

  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: 35

21.12 Fluency practice within 20

Fluency practice within 20 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 20 and 17 to make a simple example about Fluency practice within 20.

  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 Fluency practice within 20.

Worked Example 2

Problem: Use 14 and 13 to make a simple example about Fluency practice within 20.

  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 Fluency practice within 20.

Worked Example 3

Problem: Use 18 and 2 to make a simple example about Fluency practice within 20.

  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 Fluency practice within 20.

Worked Example 4

Problem: Use 11 and 13 to make a simple example about Fluency practice within 20.

  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 Fluency practice within 20.

Worked Example 5

Problem: Use 17 and 8 to make a simple example about Fluency practice within 20.

  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 Fluency practice within 20.

Worked Example 6

Problem: Use 6 and 19 to make a simple example about Fluency practice within 20.

  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 Fluency practice within 20.

Worked Example 7

Problem: Use 12 and 1 to make a simple example about Fluency practice within 20.

  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 Fluency practice within 20.

Worked Example 8

Problem: Use 17 and 1 to make a simple example about Fluency practice within 20.

  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 Fluency practice within 20.

Worked Example 9

Problem: Use 5 and 18 to make a simple example about Fluency practice within 20.

  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 Fluency practice within 20.

Worked Example 10

Problem: Use 8 and 13 to make a simple example about Fluency practice within 20.

  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 Fluency practice within 20.

30 Review Questions and Answers

Q1. What should a Grade 2 learner understand about Facts subtracting 0?

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

Q2. What should a Grade 2 learner understand about Facts subtracting 1?

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

Q3. What should a Grade 2 learner understand about Facts from 10?

Answer: Facts from 10 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 Facts from doubles?

Answer: Facts from doubles 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 Using addition facts?

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

Q6. What should a Grade 2 learner understand about Counting back?

Answer: Counting patterns organize numbers and help with addition, subtraction, and number relationships.

Q7. What should a Grade 2 learner understand about Counting up?

Answer: Counting patterns organize numbers and help with addition, subtraction, and number relationships.

Q8. What should a Grade 2 learner understand about Subtracting 5?

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 Subtracting 10?

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

Q10. What should a Grade 2 learner understand about Fact families?

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

Q11. What should a Grade 2 learner understand about Missing-number subtraction?

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

Q12. What should a Grade 2 learner understand about Fluency practice within 20?

Answer: Fluency practice within 20 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 Facts subtracting 0?

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

Q14. What should a Grade 2 learner understand about Facts subtracting 1?

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

Q15. What should a Grade 2 learner understand about Facts from 10?

Answer: Facts from 10 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 Facts from doubles?

Answer: Facts from doubles 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 Using addition facts?

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

Q18. What should a Grade 2 learner understand about Counting back?

Answer: Counting patterns organize numbers and help with addition, subtraction, and number relationships.

Q19. What should a Grade 2 learner understand about Counting up?

Answer: Counting patterns organize numbers and help with addition, subtraction, and number relationships.

Q20. What should a Grade 2 learner understand about Subtracting 5?

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 Subtracting 10?

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

Q22. What should a Grade 2 learner understand about Fact families?

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

Q23. What should a Grade 2 learner understand about Missing-number subtraction?

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

Q24. What should a Grade 2 learner understand about Fluency practice within 20?

Answer: Fluency practice within 20 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 Facts subtracting 0?

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

Q26. What should a Grade 2 learner understand about Facts subtracting 1?

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

Q27. What should a Grade 2 learner understand about Facts from 10?

Answer: Facts from 10 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 Facts from doubles?

Answer: Facts from doubles 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 Using addition facts?

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

Q30. What should a Grade 2 learner understand about Counting back?

Answer: Counting patterns organize numbers and help with addition, subtraction, and number relationships.