1 3 Multiplying and Dividing Real Numbers Page

1 -3 Multiplying and Dividing Real Numbers Page 9 Lesson Objective: I will be able to … • Multiply real numbers • Divide real numbers Language Objective: I will be able to … • Read, write, and listen about vocabulary, key concepts, and examples Holt Algebra 1

1 -3 Multiplying and Dividing Real Numbers When you multiply two numbers, the signs of the numbers you are multiplying determine whether the product is positive or negative. Factors Product 3(5) Both positive 15 3(– 5) One negative – 15 – 3(– 5) Both negative This is true for division also. Holt Algebra 1 15 Positive Negative Positive

1 -3 Multiplying and Dividing Real Numbers Page 9 Multiplying and Dividing Signed Numbers Multiplying and Dividing Numbers with the Same Sign WORDS NUMBERS If two numbers have the same sign, their product or quotient is positive. 4 5 = 20 – 15 ÷ (– 3) = 5 Holt Algebra 1

1 -3 Multiplying and Dividing Real Numbers Page 9 Multiplying and Dividing Signed Numbers Multiplying and Dividing Numbers with Different Signs WORDS NUMBERS Holt Algebra 1 If two numbers have different signs, their product or quotient is negative. 6(– 3) = – 18 ÷ 2 = – 9

1 -3 Multiplying and Dividing Real Numbers Example 1: Multiplying and Dividing Page 10 Signed Numbers Find the value of each expression. A. B. = – 5 = 12 The product of two numbers with different signs is negative. The quotient of two numbers with the same sign is positive. C. First substitute for x. The quotient of two numbers with different signs is negative. Holt Algebra 1

1 -3 Multiplying and Dividing Real Numbers Page 10 Your Turn 1 Find the value of each expression. A. 35 (– 5) = – 7 The quotient of two numbers with different signs is negative. B. – 6 x for x = 7 = – 6(7) First substitute 7 for x. = – 42 The product of two numbers with different signs is negative. Holt Algebra 1

1 -3 Multiplying and Dividing Real Numbers Page 8 Two numbers are reciprocals if their product is 1. A number and. Hint its reciprocal are called multiplicative Helpful inverses. You can write the reciprocal of a number by To divide by a number, you canand multiply by its multiplicative switching the numerator denominator. A inverse. whole number has a denominator of 1. Dividing by a nonzero number is the same as multiplying by the reciprocal of the number. Multiplicative inverses 1 10 = =2 5 5 Dividing by 5 is the same as multiplying by the reciprocal of 10 ÷ 5 = 2 5, which is Holt Algebra 1 . 10 ∙

1 -3 Multiplying and Dividing Real Numbers Example 2: Dividing by Fractions Example 2 Dividing by Fractions Page 11 Divide. To divide by A. , multiply by . Multiply the numerators and multiply the denominators. and have the same sign, so the quotient is positive. B. Write To divide by and negative. Holt Algebra 1 , multiply by as an improper fraction. . have different signs, so the quotient is

1 -3 Multiplying and Dividing Real Numbers Page 11 Your Turn 2 Divide: Write as an improper fraction. To divide by and , multiply by have the same signs, so the quotient is positive. Holt Algebra 1 .

1 -3 Multiplying and Dividing Real Numbers Page 10 Properties of Zero WORDS Multiplication by Zero The product of any number and 0 is 0. NUMBERS 1 · 0=0 3 ALGEBRA a· 0=0 Holt Algebra 1 0(– 17) = 0 0·a=0

1 -3 Multiplying and Dividing Real Numbers Page 10 Properties of Zero WORDS NUMBERS ALGEBRA Holt Algebra 1 Zero Divided by a Number The quotient of 0 and any nonzero number is 0. 0 =0 6 0 =0 a 0÷ 2 =0 3 0÷a=0

1 -3 Multiplying and Dividing Real Numbers Page 10 Properties of Zero Division by Zero WORDS NUMBERS ALGEBRA Division by 0 is undefined. 12 ÷ 0 Undefined a÷ 0 Undefined Holt Algebra 1 – 5 0 a 0

1 -3 Multiplying and Dividing Real Numbers Example 3: Multiplying and Dividing Page 11 with Zero Multiply or divide. 0 A. 15 Zero is divided by a nonzero number. 0 The quotient of zero and any nonzero number is 0. B. – 22 0 undefined C. – 8. 45(0) 0 Holt Algebra 1 A number is divided by zero. Division by zero is undefined. A number is multiplied by zero. The product of an number and 0 is 0.

1 -3 Multiplying and Dividing Real Numbers Page 12 Your Turn 3 Multiply or Divide: A. 0 ÷ 0 is undefined Any number divided by 0 is undefined. B. (– 12. 350)(0) = 0 Holt Algebra 1 The product of any number and 0 is 0.

Cornell Notes 1 -3 Multiplying and Dividing Real Numbers Page 13 • Fill in the Essential Question: “How do I multiply and divide with real numbers? ” • Write two or three main ideas from this lesson in the Notes section. • Write a Question for each main idea. (The answer to the question should be the main idea. ) • Summarize the answers to your questions in Holt Algebra 1 the Summary section.

Homework 1 -3 Multiplying and Dividing Real Numbers Assignment #14 • 1 -3 Homework Worksheet Holt Algebra 1