Find the LCM of Three Numbers

Start with pairs to 30 and listing multiples. Use prime factorization for the pairs to 200, where listing multiples takes too long.

Find the least common multiple of 16 sets of three numbers like 28, 16 and 21. The LCM of three numbers is the smallest number that all three divide into evenly: LCM (2, 3, 4) = 12. The directions on the page read: Find the least common multiple of each set of three numbers. An answer key is included.

Yes, both. We made it for 6th Grade factoring, and the page works the same whether it lands on a kitchen table or a center rotation. At home, most families go through it together and talk the answers out loud, and that talking is where most of the learning happens with least common multiple (LCM). In class it runs well as independent work while you pull a small group. Print one copy or thirty, whichever the day needs.

List multiples of the larger number until one is also a multiple of the smaller number, or multiply the highest power of each prime. LCM (8, 12) = 24, since 24 is the first multiple of 12 that 8 divides.

Then the larger number is the LCM. The LCM of 3 and 30 is 30, and the LCM of 150 and 25 is 150.

It gives the least common denominator for adding and subtracting fractions with unlike denominators. It also solves problems about events that repeat on different cycles.