How can 8 - 3 be turned into an addition problem?

In this lesson you will learn to rethink a subtraction problem as an addition problem by using the

additive inverse.

Let’s ReviewLet’s Review

What’s an integer?Integers include positive and negative

whole numbers as well as 0. ...-3, -2, -1, 0, 1, 2, 3 ...

Non-Examples: -5.2 0.28 -9.9 4

Let’s ReviewLet’s Review

What’s subtraction?Subtraction is the opposite of addition.

15 - 3 = 12

minuend subtrahend difference

It can be seen as the process of taking away or finding the difference between two numbers.

Let’s ReviewLet’s Review

How does one add on a number line?

8-13

-5-3-6

-9

8 + -13

-3 + -6

Let’s ReviewA Common Mistake

Subtracting the numbers like two positives and applying a sign at the end.

-6 - 3 = 3 5 - (-4) = 1--

Let’s ReviewCore Lesson

8 - = 58 + = 5

7 - = -67 + = -6(-3)

3 13(-13)

0 0

Additive Inverse

0 0

Let’s ReviewCore Lesson Additive Inverse

-2 - = 7-2 + = 7

-15 - = -21-15 + = -21

6(-6) 9

(-9)

0 0

In this lesson you learned to rethink a subtraction problem

as an addition problem by using the additive inverse.

Let’s ReviewGuided Practice

-5 -(-9)

Determine the difference of -5 - (-9) by modeling the additive inverse.

Let’s ReviewGuided Practice

-8 - 6Simplify -8 - 6 and -8 + (-6).

-8 + (-6)

Let’s ReviewExtension Activities

Create a set of 30-40 integer subtraction problems.

Rewrite each problem as an addition problem using the additive inverse. See how many you can correctly rewrite in 60 seconds.

Let’s ReviewExtension Activities

Partner Game:Each partner writes an integer subtraction problem for the other partner.

Each partner then solves the problem on his own paper by rewriting the problem as an addition problem using the additive inverse.

Both partners compare their answers.

Let’s ReviewExtension Activities

Subtracting a negative subtrahend can be one of the most confusing aspects of working with integers.

Rewrite these using the additive inverse:-16 - (-2) 7 - (-14) -3 - (-18)

What “rule” could you write to describe what’s happening?

Let’s ReviewQuick Quiz

12 + 4Simplify 12 + 4 and 12 - (-4).

12 - (-4)

Let’s ReviewQuick Quiz

Determine the difference of -10 - 7 by modeling the additive inverse.