1. Subtracting Fractions
With borrowing

2. Just like in whole number subtraction, sometimes you need to borrow when subtracting fractions.

3. Example 1: Whole number – mixed number
If you order 5 pizzas and your family eats 3 and 2/5 of them, how much pizza is left?

4. Always write the equation vertically:

5. Start with 5 pizzas:

6. Uh, oh! I can’t take 2/5 of a pizza from nothing!

7. That’s OK!
Take one pizza and turn it from a whole pizza into one with five slices! Now you have four whole pizzas and one whole pizza split into five slices!

8. Now just subtract!

9. Answer:
We have 1 and 3/5 of a pizza left.

10. Example 2: Mixed number – Mixed number
Maria’s family had a party and her mom made lasagnas. At the end of the night there were 4 and 5/8
pans of lasagna left. Maria’s mom packed up 2 and ¾ pans for her grandparents and cousins to take home. How much did they have left to eat for leftovers the next day?

11. Start with 4 and 5/8 pans of lasagna.

12. Uh, oh! I can’t subtract fractions with unlike denominators!

13. First, convert the fractions to have the same denominator.
In this case, the least common
denominator is 8.

14. Uh, oh! I can’t take 6/8 away from 5/8!

15. Now, you need to borrow a whole from the four and make it into eighths.
You already have 5/8, so adding 8/8 will give you 13/8. 1 2 9 10 3 4 11 12 5 6 13 7 8

16. Set up your equation and subtract!

17. Answer:
Maria will have 1 and 7/8 of a pan of lasagna left for leftover night.

18. Now you try!