Integer Operations

1) What’s the rule for adding integers?*If both addends are Positive:

- Add together and the sum is positive(Ex. 8 + 4 = 12)

*If both addends are Negative:- Add together and the sum is negative

(Ex. -6 + -5 = -11)*If addends have different signs:- Subtract the absolute values, and - the sum will have the sign of the larger

absolute value. (Ex. -7 + 4 = -3)

Solve the Problems

• -3 + -5 =• 4 + 7 =• (+3) + (+4) =• -6 + -7 = • 5 + 9 =• -9 + -9 =

-8

-18

14-13

7

11

2) Integer Subtraction RuleSubtracting a negative number is the same as adding a positive. Change the signs and add.

2 – (-7) is the same as

2 + (+7)

2 + 7 = 9!

Here are some more examples.

12 – (-8)

12 + (+8)

12 + 8 = 20

-3 – (-11)

-3 + (+11)

-3 + 11 = 8

Examples:1. 8 – 13

2. 6 – 14

3. - 10 – 1

4. 1 – (-2)

5. 4 – (-8)

6. -3 – (-5)

7. -7 – (-4)

= -5

= -8

= -11

= 3

= 12

= 2

= -3

When multiplying and dividing integers there are two rules:

1. When multiplying or dividing integers that have the SAME sign, the answer is POSITIVE.• Positive x positive = positive• Negative x negative = positive

+7 x +12 = +84-6 x –5 = +30

3 & 4) Multiplying and Dividing Integers

2. When multiplying or dividing integers whose signs are DIFFERENT, the answer will always be NEGATIVE.

• Positive x negative = negative• Negative x positive = negative

+8 x –4 = -32-5 x +7 = -35

Rules continued…

Let’s Practice!

What sign would the answer have in front of the integer???

-5 x -7 = ???

POSITIVE!!!

How about…

-6 x 9 = ???What sign will be in front of the answer??

NEGATIVE!!!

Try this one!

What sign will be in front of the answer???

-81 ÷ +9 = ???

NEGATIVE!!!

Practice in your notes….