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What is the Least Common Multiple of 780 and 800?

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 780 and 800 is 31200.

LCM(780,800) = 31200

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Least Common Multiple of 780 and 800 with GCF Formula

The formula of LCM is LCM(a,b) = ( a × b) / GCF(a,b).
We need to calculate greatest common factor 780 and 800, than apply into the LCM equation.

GCF(780,800) = 20
LCM(780,800) = ( 780 × 800) / 20
LCM(780,800) = 624000 / 20
LCM(780,800) = 31200

Least Common Multiple (LCM) of 780 and 800 with Primes

Least common multiple can be found by multiplying the highest exponent prime factors of 780 and 800. First we will calculate the prime factors of 780 and 800.

Prime Factorization of 780

Prime factors of 780 are 2, 3, 5, 13. Prime factorization of 780 in exponential form is:

780 = 22 × 31 × 51 × 131

Prime Factorization of 800

Prime factors of 800 are 2, 5. Prime factorization of 800 in exponential form is:

800 = 25 × 52

Now multiplying the highest exponent prime factors to calculate the LCM of 780 and 800.

LCM(780,800) = 25 × 31 × 52 × 131
LCM(780,800) = 31200