Subtracting Integers Introduction

Subtracting Integers

First, Let's Review

Adding Integers

Multiple Choice

-6 + -24 =

• 30
• -30
• -18
• 18

Multiple Choice

50 + -10 =

• 60
• 40
• -49
• -60

Multiple Choice

-5 + 10 =

• 10
• -5
• 5
• -10

Subtracting Integers

Using Tiles

Multiple Choice

Which of these expressions represents another way to show 8 - 3?

• 8 + (-3)

• 8 - (-3)

• -8 + 3

This says -9 - (-2)

Multiple Choice

Which of these expressions represents another way to show (-9) - (-2)

• -9 + 2

• -9 + (-2)

• -9 - 2

What if we want to take away something that is not there?

9 - (-2)

Zero Pairs

• If you add a red and a black at the same time, they cancel each other out.

• Now, there are two red to take away.

• If we take away the two red, how many blacks are left?

Or 9 - (-2) = 11

Subtracting is the same as adding the opposite!

9 - (-2) is the same as 9 + 2

-7 - 3 = -7 + (-3)

Subtracting is the same as adding the opposite!

Let's practice rewriting subtraction problems as addition problems.

Multiple Choice

Rewrite the problem as an addition problem:

6 - 4

• 6 + 4

• 6 + (-4)

Multiple Choice

Rewrite the problem as an addition problem:

-5 - (-3)

• -5 + (-3)

• -5 + 3

Multiple Choice

Rewrite the problem as an addition problem:

6 - (-9)

• 6 + 9

• 6 + (-9)

Multiple Choice

12 − 19

• -12 + 19

• -12 + (-19)

• 12 + 19

• 12 + (-19)

Multiple Choice

-1 − 5

• -1 + 5

• -1 + (-5)

• 1 + 5

• 1 + (-5)

Multiple Choice

-3 − (-9)

• -3 + (-9)

• 3 + 9

• 3 + (-9)

• -3 + 9

Subtracting Integers

Rewrite as an addition problem

- Change subtraction to addition

- Change the sign of the second number

- Follow the rules for addition

Multiple Choice

-13 - 3 =

• 10

• -10

• -16

• 16

Multiple Choice

3 - 11 =

• -8

• 8

• 14

• -14

Multiple Choice

-5 - (-6) =

• 1

• -1

• 11

• -11

Multiple Choice

-12 - 3 =

• -15

• 15

• 9

• -9

Multiple Choice

-11 - (-11) =

• 0

• 22

• -22

• 11

Poll

How do you feel about the rules for subtracting integers?

• Great! : D

• Pretty Good : ))

• Good : )

• Okay : /

• Not so Good : (