Finding the Least Common Denominator of Three Fractions

The least common denominator of two or more fractions is the smallest number that can be divided evenly by each of the fractions' denominators.  You can determine the LCM (least common multiple)  by finding multiples of the denominators of the fractions.

Find the least common denominator of the following fractions:  5/12, 7/36, and 3/8.

8, 16, 24, 36
12, 24, 36
36

The least common denominator is 36.

Least Common Multiple

Find the least common denominator of 6, 8, 12.

6, 12, 18, 24
8, 16, 24
12, 24

The least common multiple is 24.

GED Skill: Add fractions with common denominators

The Smith family is having a party with 11 guests. They are serving 1/4 lb. burgers. If the average is 1 1/2 burgers per guest, how many pounds of hamburger should be bought?