Least Common Multiples Least Common Multiples Finding least common multiples is a preliminary step in adding and subtracting fractions with unlike denominators. It is also the strategy used to solve problems when two unequal quantities need to match up. For example, suppose you have two wheels of two different sizes or circumferences. Spreadsheets are another way of helping students see how common multiples can be found by generating a series of numbers and then finding the first common number. This is particularly helpful if you are using more than two numbers.
Spreadsheets are another way of examining series or patterns of numbers.
These exercises can also be useful in relating common multiples to adding or subtracting fractions with unlike denominators. To show students how least common multiples are achieved using two and three numbers. When the purpose of teaching common multiples is to find the least common multiple for fractions, the numbers used should stay within the range of fractions encountered in normal life. It may be helpful to have students organize their searches for common multiples on a grid such as the one below. The top number is the factor used to multiply the numbers in the problems.