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 

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

Adding/ Subtracting mixed numbers

100

11 3/4 - 4 2/4 = ?

7 1/14

200

15 3/10 + 2 2/5 = ?

17 7/10

300

7 2/7 - 4 3/14 = ?

3 1/14

400

100 - 27 5/8 = ?

72 3/8

500

18 2/3 - 16 5/6 = ?

1 5/6

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

How many wholes can we make from 16/4?

4

400

What is the FRACTION left over after removing the wholes from 16/7?

2/7

500

How can we express 5.6 as a mixed number (whole number and fraction?

5 and 6/10