Adding & Subtracting Fractions with Unlike Denominators

Adding Fractions with Unlike Denominators

100

1/4 + 2/3 = 

11/12

200

4/9 + 1/6 =

*write your answer in simplest form 

11/18

300

3/4 + 1/9 =

31/36

400

1/2 + 1/3 =

5/6

500

1/4 + 3/7 =

19/28

Subtracting Fractions with Unlike Denominators

100

4/5 - 1/3 =

7/15

200

4/3 - 2/7 =

22/21 

300

3/4 - 1/9 =

23/36

400

6/7 - 1/2 =

5/14

500

9/10 - 1/4 =

*Write your answer in simplest form 

13/20

Least Common Denominator

100

1/2 and 3/5

LCD: 10

200

5/12 and 2/9

LCD: 36

300

1/7 and 4/8

LCD: 56

400

9/10 and 5/6

LCD: 30

500

1/4 and 2/3

LCD: 12

Fraction Understanding

100

If the denominators are the same for two fractions, do we have to find the least common denominator (LCD)?

No, we can add or subtract the fractions as is.

200

What is the first thing you do when you are adding or subtracting fractions with unlike denominators?

Find the least common denominator (LCD) for all of the fractions.

300

Add and subtract 3/4 and 1/5

15/20 and 4/20 

Addition = 19/20 

Subtraction= 11/20

400

What are 2 ways you can get two fractions with unlike denominators to have the same denominator?

1) Find the least common denominator (LCD)

2) Multiply the two denominators by one another

500

What is the last step in the process of adding and subtracting fractions?

Reduce or simplify

Factors Review

100

List the factors of 18

1, 2, 3, 6, 9, 18

200

List the factors of 30 

1, 2, 3, 5, 6, 10, 15, 30

300

List the factors of 21 

1, 3, 7, 21

400

List the factors of 9 

1, 3, 9

500

List the factors of 8

1, 2, 4, 8