Chapter 1, Section 9Multiplying and Dividing Integers

Ms. Dewey-Hoffman, 2009

Page 2

Warm Up

Adding and Subtracting Integers

1) 4 + (-6) + 3 =

2) -72 + 36 + (-6) + (-18) =

3) -32 + 2 + (-10) =

4) -7 – (-7) + (-7) =

Page 3

Multiplying Integers

To prove that the product of a negative number and a positive number is negative, write the problem as repeated addition.

4(-10) = (-10) + (-10) + (-10) + (-10) = -40

Examples:

2(-6) =

4(-3) =

7(-2) =

21(-1) =

Page 4

Multiplying Integers

The answer (product) of two integers with the same sign is Positive.

The answer (product) of two integers with different signs is Negative.

The answer (product) of zero and any integer is zero.

-3(-4) • -4 =

-4 • 8(-2) =

6(-3)(5) =

-7 • (-14) • 0 =

An even number of negative numbers = a positive answer.

An odd number of negative numbers = a negative answer.

Page 5

Dividing Integers

Use the same rules of multiplying as dividing.

The quotient of two integers with the same sign is positive.

The quotient of two integers with different signs is negative.

Remember that division by zero is undefined.

-32 ÷ 8 =

-48 ÷ (-6) =

-56 ÷ (-4) =

-140 ÷ 5 =

Page 6

#5

Do the worksheets.

Even Numbered Problems.

Do the work on a SEPARATE sheet of paper, follow the homework guidelines.