Mrs. Himmel's Class

Monday, May 10, 2010

Integer Rules

Subtraction

1. Change the subtraction problem into addition.

2. Change the second numbers' sign to the opposite.

3. Follow addition rules.

Examples

Original Problem

-9 - (-7)=

After you change the problem:

-9 + 7 = -2

Addition

1. Like signs you add and the answer will have the same sign.

2 Unlike signs you subtract and keep the sign of the largest absolute value.

Examples

Like signs

-6 + -5 = -11

Unlike signs

-6 + 5 = -1

Multiplication and Division

1. Like signs ALWAYS have a positive answer.

Examples:

(-6)(-9)= +54

-70 ÷ (-10) = + 7

2. Unlike signs ALWAYS have a negative answer.

Examples:

-42 ÷ 7 = -6

-2 x 3 = -6