Question

lcm of 12 15 18 and 20

Answer 1

Answer:

The instructions to find the LCM of 12, 15, 18 and 20 are the next:

1. Decompose all numbers into prime factors

12 2 6 2 3 3 1 15 3 5 5 1 18 2 9 3 3 3 1 20 2 10 2 5 5 1

2. Write all numbers as the product of its prime factors

Prime factors of 12 = 22 . 3

Prime factors of 15 = 3 . 5

Prime factors of 18 = 2 . 32

Prime factors of 20 = 22 . 5

3. Choose the common and uncommon prime factors with the greatest exponent

Common prime factors: None

Common prime factors with the greatest exponent: None

Uncommon prime factors: 2 , 3 , 5

Uncommon prime factors with the greatest exponent: 22, 32, 51

4. Calculate the Least Common Multiple or LCM

Remember, to find the LCM of several numbers you must multiply the common and uncommon prime factors with the greatest exponent of those numbers.

LCM = 22. 32. 51 = 180