LCM( 16, 12, 18, 20, 16 ) = 720
Step 1: Write down factorisation of each number:
16 = 2 · 2 · 2 · 2
12 = 2 · 2 · 3
18 = 2 · 3 · 3
20 = 2 · 2 · 5
16 = 2 · 2 · 2 · 2
Step 2 : Match primes vertically:
16 | = | 2 | · | 2 | · | 2 | · | 2 | ||||||
12 | = | 2 | · | 2 | · | 3 | ||||||||
18 | = | 2 | · | 3 | · | 3 | ||||||||
20 | = | 2 | · | 2 | · | 5 |
Step 3 : Bring down numbers in each column and multiply to get LCM:
16 | = | 2 | · | 2 | · | 2 | · | 2 | ||||||||
12 | = | 2 | · | 2 | · | 3 | ||||||||||
18 | = | 2 | · | 3 | · | 3 | ||||||||||
20 | = | 2 | · | 2 | · | 5 | ||||||||||
LCM | = | 2 | · | 2 | · | 2 | · | 2 | · | 3 | · | 3 | · | 5 | = | 720 |