2. &
dding
ubtracting
ractions

3. Adding & Subtracting Fractions Teacher Notes:
Use this presentation to teach the steps for adding and subtracting fractions with unlike denominators.
It is assumed that students have a thorough understanding of the process for making equivalent fractions.
CLICK HERE to view a demonstration with opportunities for students to practice making equivalent fractions.

4. Step 1: Find a
common
denominator
to add
these fractions. +

5. +
Step 1: Find a
common
denominator
to add
these fractions.
Count by 2's
2, 4, 6, 8, 10, 12, 14, 16, 18, 20
Count by 7's
7, 14, 21, 28, 35…

6. Step 3: Add the numerators
x 7 7
Step 2: Make equivalent
fractions. =
X 7
x 2 6
Step 3: Add the numerators = +
7 + 6 = 13
x 2 13
Step 4: Simplify

7. +
Step 1: Find a
common
denominator
to add
these fractions.
Count by 7's
7, 14, 21, 28, 35, 42, 49, 56, 63
Count by 5's
5, 10, 15, 20, 25, 30, 35, 40, 45

8. Step 3: Add the numerators
x 5 15
Step 2: Make equivalent
fractions. =
X 5
x 7 7
Step 3: Add the numerators + =
x 7
= 22 22
Step 4: Simplify

9. +
Step 1: Find a
common
denominator
to add
these fractions.
Count by 7's
7, 14, 21, 28, 35, 42, 49, 56, 63
Count by 8's
8, 16, 24, 32, 40, 48, 56, 64, 72

10. Step 3: Add the numerators32
x 8
Step 2: Make equivalent
fractions. =
x 8 21
x 7
Step 3: Add the numerators + =
= 53
x 7 53
Step 4: Simplify

11. Step 1: Find a
common
denominator
to add
these fractions. -
Count by 5's
5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55
Count by 11's
11, 22, 33, 44, 55, 66, 77…

12. Step 3: Add the numerators15
Step 2: Make equivalent
fractions.
x 5 =
x 5 11
x 11
Step 3: Add the numerators =
= 4 -
x 11 4
Step 4: Simplify

13. Try These A D E B F C

14. Answers On Next Slide
Each click on the next slide reveals an answer.
Check your papers.
If you discover an incorrect answer, be able to explain your mistake.

15. Try These 10 9 17 27 A D 41 28 13 12 B E 19 20 26 21 C F