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What is the Least Common Multiple of 7 and 8?

Least common multiple or lowest common denominator (lcd) can be calculated in two way; with the LCM formula calculation of greatest common factor (GCF), or multiplying the prime factors with the highest exponent factor.

Least common multiple (LCM) of 7 and 8 is 56.

LCM(7,8) = 56

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Least Common Multiple of 7 and 8 with GCF Formula

The formula of LCM is LCM(a,b) = ( a × b) / GCF(a,b).
We need to calculate greatest common factor 7 and 8, than apply into the LCM equation.

GCF(7,8) = 1
LCM(7,8) = ( 7 × 8) / 1
LCM(7,8) = 56 / 1
LCM(7,8) = 56

Least Common Multiple (LCM) of 7 and 8 with Primes

Least common multiple can be found by multiplying the highest exponent prime factors of 7 and 8. First we will calculate the prime factors of 7 and 8.

Prime Factorization of 7

Prime factors of 7 are 7. Prime factorization of 7 in exponential form is:

7 = 71

Prime Factorization of 8

Prime factors of 8 are 2. Prime factorization of 8 in exponential form is:

8 = 23

Now multiplying the highest exponent prime factors to calculate the LCM of 7 and 8.

LCM(7,8) = 71 × 23
LCM(7,8) = 56