Algebra 1.3Multiplying and Dividing Real Numbers

Language Goal Students should be able to explain how to perform

multiplication and division with real numbers.

Math Goal Students should be able to multiply and divide

real numbers.

Essential Question How do you translate between written word and

math in order to solve real-world problems?

Learning Targets

Warm-up Adding Integers Review

1. – 4 + 9 2. -8 + - 21

3. - 20 + 7 4. 6 + x when x = -3

Written AlgebraDirections: Write each expression two ways using words!

1. w + 9 2. 3. y – 3

4. 6(4 + m) 5. 9y - 8

Warm-up

Homework Check

Reciprocal:

Multiplicative Inverse:

Vocabulary

Two numbers are a reciprocal if their product is one.

Think about flipping a fraction:

reciprocal is

A number and its reciprocal.

Same Signs = Always Positive

Different Signs = Always Negative

Multiplying and Dividing Fractions

-5(-4) = 20

-9(6) = -54 = -9

But plus signs along the diagonal

Put negative signs everywhere else

Think Tic Tac Toe

Multiply or Divide

1. -125 2. 8x for x = 2 3.

4. 5. -56 ÷ 8

Practice Problems

Multiplying fractions◦ Numerator times numerator◦ Denominator times denominator◦ Simplify the fraction

Review of Fractions

4−5×−36

Dividing Fractions◦ Keep the first fraction◦ Switch the sign from multiplication to division◦ Flip the second fraction

Review of Fractions

3−4÷12

1. 2.

3. -7 4.

Fraction Practice

Words Numbers AlgebraMultiplication by Zero    

Zero Divided by a Number    

Division by Zero    

Properties of Zeros

The product of any number and 0 is 0

·0 = 0

0(-17) = 0

a·0 = 0

0·a = 0

The quotient of 0 and any nonzero number is 0

0 ÷ = 0

a≠0

Division by 0 is undefined

12 ÷ 0

undefined

a ÷ 0

undefined

1. 0 15 2. 24 0

3. 0(78) 4. 0 6

Extra Practice on Properties

RED = NEGATIVE numberBLACK = POSITIVE number

WAR

Review

Lesson Quiz