First, a fraction is numerator/demonenator Give them all common denomenators. You must multiply the top and bottom of each fraction by a number to make all the bottom numbers the same. For example if you had 2/3, 1/6, and 1/3...multiply the top and bottom of 2/3 by 2 to make 4/6, multiply the top and bottom of 1/3 by 2 to make 2/6, and 1/6 does not need to be changed because it already has a 6 in the denomenator. It is very important you also are sure to change the top and bottom by the same number or the answers will not turn out.