What is the least common multiple of 16 and 20?

Answer 1

The LCM of 16 and 20 is 80.

The LCM is the product of the numbers divided by their GCF.

The GCF of 16 and 20 is 4. (We know the GCF can't be any larger than the difference between the two numbers. Trying 4 divided into 16 and 20 shows that it is a factor of both).

16 * 20 / 4 = 80, which is the LCM.

The LCM is: 80

Method of prime factorization: Expressing each number as the product of prime numbers.

20 = 2x2x5

16 = 2x2x2x2

H.C.F. of 20 and 16 = 2x2 = 4.

L.C.M.(20,16) = H.C.F.(20,16) x Product of uncommon numbers in prime factorizations

L.C.M.(20,16) = 4 x 5x2x2 = 4x20 = 80.

Alternate method:

Multiples of 20 are 20, 40, 60, 80, 100, 120, 140, 160, 180,...

Multiples of 16 are 16, 32, 48, 64, 80, 96, 112, 128, 144, 160,...

As we can see that there exists infinite common multiples but the least common multiple is 80.

Answer 2

It is 80

Answer 3

80

Answer 4

80.

Answer 5

80

Answer 6

3