**Middle School Number Sense Lesson 91: Finding the Additive Inverse**

This concept is similar to

**Reciprocal**, which is another name for

*multiplicative inverse*. These problems have appeared

**4 times**this year, with a median placement at

**question # 27**.

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The

**additive inverse**of a number is the result you get when you

**subtract it from 0**. It is also known as the

**opposite**of a number. To find a number’s additive inverse, simply

**change its sign**(from positive to negative or from negative to positive).

**Example 1: The additive inverse of -3 is ___**

- Change the sign
- The answer is
**3**

**Example 2: The additive inverse of 13.2 is ___**

- Change the sign
- The answer is
**-13.2**

**Example 3: The additive inverse of -4/7**

**is ___**

- Change the sign
- The answer is
**4/7**

**Example 4:**

**The additive inverse of 7**

^{2}is ___1. Simplify: 7

^{2}= 49

2. Change the sign:

**-49**

**Example 5: The sum of 9 and its additive inverse is ___**

- The additive inverse of 9 is
**-9** - 9 + (-9) =
**0**. 0 will*always*be the answer to this type of question.

**Example 6: The product of 9/7**

**and its additive inverse is ___**

- The additive inverse of 9/7 is
**-9/7** - 9/7 x -9/7 =
**-81/49**. Leave this fraction as is unless the question asks for a mixed number.

**Example 7: The opposite of the additive inverse of -6 is ___**

- The opposite and additive inverse mean the same thing. They cancel each other out (because you’re changing the sign twice).
- The answer is
**-6**

**Up Next for Middle School: MoneyDiscount**