LCM( 20, 15, 16, 18 ) = 720
Step 1 : Place the numbers inside division bar:
20 | 15 | 16 | 18 |
Step 2 : Find a prime number which can divide at least two of your numbers.
In this example we can divide by 2. If any number is not divisible by 2 write it down unchanged.
2 | 20 | 15 | 16 | 18 |
10 | 15 | 8 | 9 |
Step 3 : Repeat Step 2 until you can no longer divide.
2 | 20 | 15 | 16 | 18 |
2 | 10 | 15 | 8 | 9 |
5 | 15 | 4 | 9 |
2 | 20 | 15 | 16 | 18 |
2 | 10 | 15 | 8 | 9 |
5 | 5 | 15 | 4 | 9 |
1 | 3 | 4 | 9 |
2 | 20 | 15 | 16 | 18 |
2 | 10 | 15 | 8 | 9 |
5 | 5 | 15 | 4 | 9 |
3 | 1 | 3 | 4 | 9 |
1 | 1 | 4 | 3 |
Since there are no primes that divides at least two of given numbers, we conclude that the LCM is a product of starting numbers.
LCM = 20 · 15 · 16 · 18 = 720