Least Common Multiple Worksheets
Free printable LCM worksheets. Find the least common multiple of two numbers, with an answer key. Answers kept small enough to work with by hand.
Each question gives two numbers and asks for the smallest number both divide into: the least common multiple of 8 and 6 is 24. Answers stay inside a range a student can reach by listing multiples rather than by algorithm.
That matters more than it sounds. Two numbers chosen at random can easily have an LCM in the thousands - 47 and 53 give 2,491 - which is a correct answer to a question no student can check. The pairs here are built so listing multiples still works.
What this worksheet covers
- Find the least common multiple of two numbers
- List multiples until the first shared one appears
Common Core standards
- 6.NS.B.4 Find the greatest common factor and least common multiple of two whole numbers.
Frequently asked questions
What is the least common multiple?
The smallest number that both numbers divide into exactly. For 8 and 6 it is 24: 8 goes in three times, 6 goes in four times, and nothing smaller works for both.
How do you find it?
List the multiples of each number until one appears in both lists. Or multiply the two numbers and divide by their greatest common factor, which is the same answer with less writing.
What is LCM used for?
Adding and subtracting fractions with different denominators. The least common multiple of the two denominators is the denominator to convert both to, which is why this is taught right before that.
How large do the answers get?
They stay inside a few hundred. Listing multiples has to remain a way to check the answer, and it stops being one somewhere around a thousand.