LCM( 3, 2, 10, 20, 1 ) = 60
Step 1: Write down factorisation of each number:
3 = 3
2 = 2
10 = 2 · 5
20 = 2 · 2 · 5
1 = 1
Step 2 : Match primes vertically:
3 | = | 3 | ||||||||
2 | = | 2 | ||||||||
10 | = | 2 | · | 5 | ||||||
20 | = | 2 | · | 2 | · | 5 | ||||
1 | = | 1 |
Step 3 : Bring down numbers in each column and multiply to get LCM:
3 | = | 3 | ||||||||||
2 | = | 2 | ||||||||||
10 | = | 2 | · | 5 | ||||||||
20 | = | 2 | · | 2 | · | 5 | ||||||
1 | = | 1 | ||||||||||
LCM | = | 1 | · | 2 | · | 2 | · | 3 | · | 5 | = | 60 |