# Spectrum Math Grade 7 Chapter 1 Lesson 3 Answer Key Subtraction as an Inverse Operation

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 = ____
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 = _____
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) = ____
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) = ____
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 = ____
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 = ____
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) = ____
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) = ____
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 = ____
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 = ____
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) = ____
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) = ____
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 = ____
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 = _____
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) = ____
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) = ____
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 = ____
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 = _____
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) = ____
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) = ____
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 = ____
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 = ____