Download Lesson 3.9 Dividing Fractions and Mixed Numbers

Lesson 3.9
Dividing Fractions and Mixed Numbers
Goal: Divide Fractions and Mixed Numbers
Vocabulary:
Reciprocal: Two nonzero numbers whose product is 1 are reciprocals
Example:
3
9
is the reciprocal of .
9
3
Using Reciprocals to Divide:
Words: To divide by any nonzero number, multiply by its reciprocal
Numbers:
3 2
3
3
÷ =
x
4 3
4
2
Can you simplify
=
9
8
9
?
8
Example 1: Dividing a Fraction by a Fraction
3 9
÷
= Multiply by the reciprocal (S.I.R= Same Inverse Reciprocal)
5 10
3
x
5
=
(remember to simplify your answer if possible)
Example 2: Dividing a Fraction by a Whole Number
The steps are the same! Multiply by the reciprocal
3
÷6
8
(Make the whole number a fraction by putting a 1 under it then find the reciprocal)
Guided Practice: Find the quotient. Simplify, if possible.
1.
5
1
÷
12 10
2.
8 4
÷
3 9
3.
3
÷9
4
4.
2
÷8
5
Independent Practice
Write the reciprocal of the number.
1.
1
5
2. 2
3. 1
4
5
4. 3
6
11
Find the quotient. Then check your answer.
5.
2 1
÷
9 3
6.
3 5
÷
4 8
7.
4 9
÷
9 20
8.
2 5
÷
3 18