Math Word Problems Demystified - A Self Teaching Guide

To add or subtract fractions:

1. Find the LCD.


2. Change the fractions to higher terms.


3. Add or subtract the numerators. Use the LCD.


4. Reduce or simplify the answer if necessary.

EXAMPLE:Add

3

4

þ

5

6

þ

2

3

:

SOLUTION:

Use 12 as the LCD.

3

4

¼

9

12

5

6

¼

10

12

þ

2

3

¼

8

12

27

12

¼ 2

3

12

¼ 2

1

4

EXAMPLE:Subtract

9

10

3

8

:

SOLUTION:

Use 40 as the LCD.

9

10

¼

36

40

3

8

¼

15

40

21

40

To multiply two or more fractions, cancel if possible, multiply numerators,

and then multiply denominators.

EXAMPLE:Multiply

3

8



4

9

:

20 REFRESHER II Fractions