1. Dividing Fractions Divide Whole Numbers and Unit Fractions
Divide Unit Fractions by Whole Numbers
Objective:

2. Let’s Start with some Basics
What is a Unit Fraction?
What is the Reciprocal?

3. A Unit Fraction is a Fraction that has a Numerator of 1
What is a Unit Fraction?
A Unit Fraction is a Fraction that has a Numerator of 1
Examples: 1/ / /12

4. Another name for Reciprocal: Multiplicative Inverse
What is a Reciprocal?
The reciprocal of a number is: 1 divided by the number Examples:  • the reciprocal of 2 is 1/2 (half) • the reciprocal of 10 is 1/10 (=0.1)
Another name for Reciprocal: Multiplicative Inverse
What you multiply by a number to get 1  Example: 8 × (1/8) = 1 In other words: when we multiply a number by its "Multiplicative Inverse" we get 1.

5. Write the reciprocal of each number.
Writing a Reciprocal
Write the reciprocal of each number.
a. 9 9 1 1 9
9 =
so the reciprocal is 7 8 8 7 b. = 3 4 4 3 c. = 7 1 1 7 = d. 7
so the reciprocal is

6. Dividing a Whole Number by a Unit Fraction
Example: ÷ 1/2
Standard Algorithm:
Keep- Flip-Change (KFC Method)
Keep: Keep the 1st Fraction exactly the same
NOTE: Remember, to write a Whole Number as a Fraction, put a 1 as the denominator
5/1
Flip: Flip the sign from Division to Multiplication
5/1 x ____
Change: Change the 2nd Fraction by finding it’s reciprocal
5/1 x 2/1=
Now, Solve

7. Each circle is divided into eights. You have 24 pieces.
Suppose you have three large pizzas and you want to divide
them into eighths. How many pieces would you have?
This model helps us see how we can divide a whole number by a fraction.
Each circle is divided into eights. You have 24 pieces.
So, 3 ÷ 1/8 = 24 pieces.

8. ♫ "Dividing fractions, as easy as pie,
To divide a fraction, multiply by the reciprocal of the fraction.
You can remember this by thinking “invert and multiply.” OR
♫ "Dividing fractions, as easy as pie,
Flip the second fraction, then multiply.
And don't forget to simplify,
Before it's time to say goodbye" ♫

9. Let’s Practice

14. Dividing a Unit Fraction by a Whole Number Example: 1/5 ÷ 4 Keep: Keep the 1st Fraction the same 1/5 ÷ 4= Flip: Flip the sign from Division to Multiplication 1/5 x 4… Change: Change the 2nd fraction / Find the Reciprocal 1/5 x ¼= Solve: Solve the problem 1/5 x ¼= 1/20

18. Your turn….Solve the following problems in your math notebook 1/3 ÷ 2= 6 ÷ 1/7= 1/9 ÷ 3= 10 ÷ 1/8=

20. You will be given a set of problems now to solve with an Elbow Partner Take your time. Use your notes. Work carefully In 10 minutes, we will go over these problems