This handy **Spectrum Math Grade 7 Answer Key**** Chapter 1 Lesson 1.3 Subtraction as an Inverse Operation** provides detailed answers for the workbook questions.

## Spectrum Math Grade 7 Chapter 1 Lesson 1.3 Subtraction as an Inverse Operation Answers Key

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

7 – 4 = 7 + (-4)

**Write an equivalent equation using the additive inverse.**

Question 1.

a. 8 – 3 = ____

Answer: 5

8 – 3 = 8 + (-3) = 5

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

b. 9 – 2 = _____

Answer: 7

9 – 2 = 9 + (-2) = 7

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

Question 2.

a. 12 + (-7) = ____

Answer: 5

12 + (-7) = 12 – 7 = 5

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

b. 8 + (-12) = ____

Answer: -4

8 + (-12) = 8 – 12 = -4

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

Question 3.

a. 52 – 13 = ____

Answer: 39

52 – 13 = 52 + (-13) = 39

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

b. 23 – 10 = ____

Answer: 13

23 – 10 = 23 + (-10) = 13

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

Question 4.

a. 67 + (-11) = ____

Answer: 56

67 + (-11) = 67 – 11 = 56

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

b. 45 + (-6) = ____

Answer: 39

45 + (-6) = 45 – 6 = 39

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

Question 5.

a. 30 – 15 = ____

Answer: 15

30 – 15 = 30 + (-15) = 15

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

b. 74 – 23 = ____

Answer: 51

74 – 23 = 74 + (-23) = 51

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

Question 6.

a. 3 + (-56) = ____

Answer: -53

3 + (-56) = 3 – 56 = -53

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

b. 62 + (-32) = ____

Answer: 30

62 + (-32) = 62 – 32 = 30

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

Question 7.

a. 87 – 85 = ____

Answer: 2

87 – 85 = 87 + (-85) = 2

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

b. 54 – 20 = _____

Answer: 34

54 – 20 = 54 + (-20) = 34

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

Question 8.

50 + (-17) = ____

Answer: 33

50 + (-17) = 50 – 17 = 33

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

b. 41 + (-12) = ____

Answer: 29

41 + (-12) = 41 – 12 = 29

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

Question 9.

a. 89 – 57 = ____

Answer: 32

89 – 57 = 89 + (-57) = 32

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

b. 46 – 40 = _____

Answer: 6

46 – 40 = 46 + (-40) = 6

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

Question 10.

a. 96 + (-20) = ____

Answer: 76

96 + (-20) = 96 – 20 = 76

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

b. 94 + (-90) = ____

Answer: 4

94 + (-90) = 94 – 90 = 4

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

Question 11.

a. 83 – 67 = ____

Answer: 16

83 – 67 = 83 + (-67) = 16

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

b. 98 – 34 = ____

Answer: 64

98 – 34 = 98 + (-34) = 64

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

Question 12.

a. – 76 + (-20) = ____

Answer: -96

– 76 + (-20) = – 76 – 20 = -96

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.

b. 90 + (-76) = _________

Answer: 14

90 + (-76) = 90 – 76 = 14

Subtraction is the same as the process of adding the additive inverse, or opposite, of a number to another number.