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

Least Common Denominator

100

1/2 and 3/5

10

200

5/12 and 2/9

36

300

1/7 and 4/8

56

400

9/10 and 5/6

30

500

1/4 and 2/3

12

Understanding Fractions

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 multiples of the two denominators.

300

What is the THIRD step when adding and subtracting fractions with unlike denominators?

Find the Least Common Multiple/Least Common Denominator.

400

What is the SECOND step in adding and subtracting fractions with unlike denominators?

Finding/identifying the common multiples.

500

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

Change your denominators to common denomintors and then add/subtract.

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