LCM( 5, 20, 2, 8 ) = 40
Step 1: Write down factorisation of each number:
5 = 5
20 = 2 · 2 · 5
2 = 2
8 = 2 · 2 · 2
Step 2 : Match primes vertically:
5 | = | 5 | ||||||
20 | = | 2 | · | 2 | · | 5 | ||
2 | = | 2 | ||||||
8 | = | 2 | · | 2 | · | 2 |
Step 3 : Bring down numbers in each column and multiply to get LCM:
5 | = | 5 | ||||||||
20 | = | 2 | · | 2 | · | 5 | ||||
2 | = | 2 | ||||||||
8 | = | 2 | · | 2 | · | 2 | ||||
LCM | = | 2 | · | 2 | · | 2 | · | 5 | = | 40 |