What is LCM?
The Least Common Multiple (LCM) is like finding the perfect meeting time for all your friends' schedules!
It's the smallest number that is a multiple of each number in your set. When working with three or four numbers, we use the same methods as with two numbers, just with a few more steps!
How to Find LCM of Three or Four Numbers
1️⃣ List the multiples of each number until you find a common one
2️⃣ Use prime factorization - multiply the highest power of each prime number
3️⃣ Check your answer by seeing if all numbers divide evenly into it
Let's Practice Together!
Example 1: Find LCM of 4, 6, and 8
Let's use prime factorization:
4 = 22
6 = 2 × 3
8 = 23
Now take the highest power of each prime: 23 × 3 = 8 × 3 = 24
Example 2: Find LCM of 3, 5, 6, and 10
Let's try listing multiples:
Multiples of 3: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30, ...
Multiples of 5: 5, 10, 15, 20, 25, 30, ...
Multiples of 6: 6, 12, 18, 24, 30, ...
Multiples of 10: 10, 20, 30, ...
The smallest number in all lists is 30!
Try It Yourself!
Find the LCM of: , ,
Parent Tips 🌟
- Connect to real life: Use examples like planning when three different events repeat (soccer every 3 days, piano every 5 days, art every 6 days) to show practical LCM use.
- Factor tree fun: Make prime factorization into a game by creating "factor trees" with your child - the more creative the tree, the better!
- Calculator check: After finding LCM manually, let your child verify it with a calculator to build confidence in their answers.