Page 86 - Math Course 1 (Book 1)

Dividing Rational Numbers

Mo. 2

Lesson 7
Key Concept

Inverse Property of
KEY CONCEPTS: Multiplication
1. Dividing positive and negative fractions
using multiplicative inverses. Words The product of a number and its
2. Use dimensional analysis to solve multiplicative inverse is 1.
a
problems. Symbols For every number , where a, b = 0,
b
b
there is exactly one number such that
a
MO. 2 - L7a a b = 1.
b a
Dividing Fractions Using
Multiplicative Inverses
Dividing Fractions

Vocabulary A-Z
Let us learn some vocabulary Words To divide by a fraction, multiply by its
multiplicative inverse.
Symbols a ÷ c = a d where b, c, d = 0
b d b c

Multiplicative Inverses Examples 1 ÷ 5 = 1 7 or 7
4 7 4 5 20
Two numbers whose product is 1 are called
multiplicative inverses.

1 1
a = 1 = x a Let’s Begin
a a

2 5 10 Find Multiplicative Inverse
x = = 1
5 2 10
Examples

6
Find the multiplicative inverse of
Reciprocals 7
6 ( 7
Two numbers whose product is 1 are called 7 6 ( =1 The product is 1.
reciprocals.
The multiplicative inverse or
Answer 6 7
reciprocal of is
7 6
2
Find the multiplicative inverse of 3
5
2 17 Write as an improper
3 =
5 5 fraction.
17 5 = 1 The product is 1.
5 17
2/5 and 5/2 are reciprocals
2
3
Answer The reciprocal of is 5
5 17
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