By: The Wonderful And Fabulous Mr. D.

By: The wonderful and fabulous Mr. D.

Yo, George, there are 2 ways to add with unlike denominators. (1) Find a common denominator by multiplying one denominator by the other denominator. Or (2) Find the LCD (least common denominator ) of the two denominators.

3 x 5 is 15 and the LCD of 3 and 5



is 15 10

3

So Add or subtract the numerators and keep the

denominators the same.



number as an fraction

First write each mix improper

Find LCD The LCD of 5 and 2 is 10. 

3 4

3 5

change to an improper fraction



Find the LCD. 5: 5, 10, 15, 20, 25, 30, 35, 40,

45

8: 8, 16, 24, 32, 40, 48……..LCD is 40 22 4

15 5

Change back to a mixed number

1st - Change any mixed #’s to improper

fractions. 2nd – Find the LCD 3rd – Find the equivalent fractions using the LCD’s 4th – add or subtract the numerators Last- change any improper fractions back to a mixed number