1. Multiplying Integers

2. Multiplying Integers Let’s model integer multiplication: 2 • -3 = -6
-6 • 5
= -30

3. Multiplying Integers
So, a positive number times a negative number is a ________ number.
Negative
And, a negative number times a positive number is a ________ number.
What is the answer to a negative times a negative?

4. Multiplying Integers Look at the pattern: -2 • 3 = -6 -2 • 2 = -4
-2 • 1 = -2
-2 • 0 = 0
-2 • -1 = ??
What is happening to the product each time?
It is increasing by 2
-2 • -1 = which is 2

5. Multiplying Integers
A negative number times a negative number is a ________ number
Positive

6. Multiplying Integers Here is a way to remember it:
Good guys are +, Bad guys are –
Coming into town is +, Leaving Town is –
Good is +, Bad is -
If a good guy (+) comes into town (+), that’s good (+)
If a good guy (+) leaves town (-), that’s bad (-)
If a bad guy (-) comes into town (+), that’s bad (-)
If a bad guy (-) leaves town (-), that’s good (+)

7. Multiplying Integers Multiply: 4(-3) -12 -2 • -9 18 (-25)(6) -150
-7 • -32
224
12(10)
120
-16(-5) 80

8. The Integer Song
Verse 4
Here is a rule that you must know when multiplying integers,
If signs are the same
The answer’s always positive.

9. The Integer Song
Verse 5
Another rule that you must know when multiplying integers,
If signs are different
The answer’s always negative.