1. Dividing Fractions
PowerPoint
Using…
Keep!
Change!
Flip!

2. doesn’t remember what he had for breakfast!
Dividing Fractions
Because with a little change to a division of fractions’ problem, you’ll be right back to multiplying!
Dividing fractions sounds hard, but if you remember how to multiply fractions, then you’re in luck!
Sparky
doesn’t remember what he had for breakfast!
We better review!

3. Multiplying Fractions Review
To multiply fractions, we multiply numerator by numerator and denominator by denominator.
𝟐 𝟑 × 𝟑 𝟒 = 𝟔 𝟏𝟐
÷𝟔 ÷𝟔 =
𝟏 𝟐
Or you can “cross-cancel” to simplify:
Don’t forget to simplify!
𝟐 𝟑 × 𝟑 𝟒 1
= 𝟏 𝟐 1 1 2

4. Dividing Fractions
By using the phrase, “keep, change, flip,” we can easily turn a division of fractions’ problem into a multiplication problem.
Dividing fractions is a tricky concept. It’s actually easier to multiply them.
“Keep, change, flip” means multiply by the reciprocal in the big leagues.
3 ft 1 in
I’m a
big leaguer!
Yeah, we can tell!
(wink-wink)

5. Remember! Think “keep, change, flip”!
Dividing Fractions
𝟐 𝟑 ÷ 𝟑 𝟒
Let’s try one!
𝟐 𝟑
Keep – The first fraction stays the same:
Remember! Think “keep, change, flip”!
𝟐 𝟑 ×
Change – Change the division
symbol to multiplication:
Flip – Flip (invert) the second
fraction:
𝟐 𝟑 ×
𝟒 𝟑

6. And just like that, we’re back
Dividing Fractions
And just like that, we’re back
to multiplying!
𝟐 𝟑 ÷ 𝟑 𝟒 =
𝟖 𝟗
𝟐 𝟑 × 𝟒 𝟑 =
Since 𝟖 𝟗 is simplified,
we’re done!
Let’s
do another one!

7. Dividing Fractions 𝟒 𝟗 ÷ 𝟖 𝟏𝟓 𝟒 𝟗 𝟒 𝟗 × 𝟒 𝟗 𝟏𝟓 𝟖 × Change: Flip:
Give this a try!
𝟒 𝟗
Keep:
Change:
𝟒 𝟗 ×
Flip:
𝟒 𝟗 ×
𝟏𝟓 𝟖

8. Or we could cross-cancel!
Dividing Fractions
𝟒 𝟗 × 𝟏𝟓 𝟖 =
𝟔𝟎 𝟕𝟐
𝟒 𝟗 ÷ 𝟖 𝟏𝟓 =
Simplify!
𝟔𝟎÷𝟐 𝟕𝟐÷𝟐 =
𝟑𝟎÷𝟔 𝟑𝟔÷𝟔 =
𝟓 𝟔
Or we could cross-cancel!
𝟒 𝟗 × 𝟏𝟓 𝟖 1 5
= 𝟓 𝟔 3 2

9. Dividing Fractions Remember, Sparky!
You can only cross-cancel after a division of fractions’ problem has been changed to multiplication.
© Mike’s Math Mall

10. Show Your Stuff!
Divide the following fractions. Simplify answers when necessary.
1) 𝟏 𝟐 ÷ 𝟐 𝟑 =
𝟏 𝟐 𝐱 𝟑 𝟐 =
𝟑 𝟒
2) 𝟐 𝟔 ÷ 𝟏 𝟐 =
𝟐 𝟔 𝐱 𝟐 𝟏 =
𝟒 𝟔
𝟐 𝟑 = 1 1
3) 𝟒 𝟗 ÷ 𝟖 𝟗 =
𝟒 𝟗 𝐱 𝟗 𝟖 =
𝟏 𝟐 2 1

11. Show Your Stuff!
Divide the following fractions. Simplify answers when necessary. 1
1) 𝟑 𝟓 ÷ 𝟑 𝟒 =
𝟑 𝟓 𝐱 𝟒 𝟑 =
𝟒 𝟓 1
2) 𝟏 𝟑 ÷ 𝟓 𝟖 =
𝟏 𝟑 𝐱 𝟖 𝟓 =
𝟖 𝟏𝟓 1 1
3) 𝟕 𝟏𝟎 ÷ 𝟏𝟒 𝟓 =
𝟕 𝟏𝟎 𝐱 𝟓 𝟏𝟒 =
𝟏 𝟒 2 2

12. How’d you do on the practice problems, Sparky?
Dividing Fractions
How’d you do on the practice problems, Sparky?
I did great!
But what about
dividing fractions with
whole numbers?
That’s actually a great question! We better take a look at that.

13. First, we need to change the 3 into a fraction by placing it over 1.
Dividing Fractions
𝟓 𝟖 ÷
÷ 𝟑 𝟏
Take a look at this one! 𝟑
First, we need to change the 3 into a fraction by placing it over 1.
𝟓 𝟖
Now we’re ready for
keep, change, flip!
Keep:
𝟓 𝟖 ×
Change:
𝟓 𝟖 × 𝟏 𝟑
= 𝟓 𝟐𝟒
Flip:

14. Here’s another example: How about a few more practice problems!
Dividing Fractions
Here’s another example:
𝟒 𝟏 ÷
÷ 𝟐 𝟕 𝟒
𝟒 𝟏 ÷ 𝟐 𝟕 =
𝟒 𝟏 × 𝟕 𝟐
Create a fraction!
= 𝟏𝟒 𝟏 2
=14 1
How about a few more practice problems!

15. Show Your Stuff!
Divide the following fractions. Simplify answers when necessary.
1) 𝟒 𝟓 ÷4=
𝟏 𝟓
2) 6÷ 𝟑 𝟒 = 8
Extension) 1 𝟑 𝟒 ÷2 𝟓 𝟖 =
𝟕 𝟒 ÷ 𝟐𝟏 𝟖 = 2
𝟐 𝟑 1
𝟕 𝟒 × 𝟖 𝟐𝟏 = 1 3