Adding & Subtracting Fractions with Unlike Denominators

Adding Fractions with Unlike Denominators

100

1/4 + 2/3 = 

11/12

200

4/9 + 1/6 =

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 or 1 1/21

300

3/4 - 1/9 =

23/36

400

6/7 - 1/2 =

5/14

500

9/10 - 1/4 =

 

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

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

Review

100

What is 5/30 in simplest form?

1/6

200

Estimate this fraction using benchmark fractions.

7/9

About 1

300

Find the sum. Use benchmark fractions to estimate.

2/5 + 6/7

1/2 + 1 = 1  1/2

400

Estimate the difference using benchmark fractions.

4/8 - 1/5 = 

1/2 - 0 = 1/2

500

What are all the prime numbers between 1-20?

There are 8 prime numbers between 1-20.

2,3,5,7,11,13,17,19