LCM( 5, 25, 75, 15 ) = 75
Step 1: Write down factorisation of each number:
5 = 5
25 = 5 · 5
75 = 3 · 5 · 5
15 = 3 · 5
Step 2 : Match primes vertically:
5 | = | 5 | ||||
25 | = | 5 | · | 5 | ||
75 | = | 3 | · | 5 | · | 5 |
15 | = | 3 | · | 5 |
Step 3 : Bring down numbers in each column and multiply to get LCM:
5 | = | 5 | ||||||
25 | = | 5 | · | 5 | ||||
75 | = | 3 | · | 5 | · | 5 | ||
15 | = | 3 | · | 5 | ||||
LCM | = | 3 | · | 5 | · | 5 | = | 75 |