Finding Common Denominators

Decide which strategy works best for a given problem:

Strategy 1: Find the LCM of the two denominators, and this will be your least
                       common denominator.

                  For example: a good common denominator for 1/6 and 1/4 is 12 because
                                      it is the least common multiple of 6 and 4.

Strategy 2: If one of the denominators is a multiple of the other, it is the
                       least common denominator.

                 For example: a common denominator for 1/2  and  1/4 is 4 because
                                    4 is a multiple of 2.

Strategy 3: If the first two strategies do not work, you can multiply the
                      two denominators together to get a common denominator.

                  For example: the least common denominator for 1/3 and 1/7 is 21,
                                      which is the sum of the denominators.