What is the Least Common Multiple of 8400 and 8420?

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 of 8400 and 8420 with GCF Formula

The formula of LCM is LCM(a,b) = ( a × b) / GCF(a,b).
We need to calculate greatest common factor 8400 and 8420, than apply into the LCM equation.

GCF(8400,8420) = 20
LCM(8400,8420) = ( 8400 × 8420) / 20
LCM(8400,8420) = 70728000 / 20
LCM(8400,8420) = 3536400

Least Common Multiple (LCM) of 8400 and 8420 with Primes

Least common multiple can be found by multiplying the highest exponent prime factors of 8400 and 8420. First we will calculate the prime factors of 8400 and 8420.

Prime Factorization of 8400

Prime Factorization of 8420

Now multiplying the highest exponent prime factors to calculate the LCM of 8400 and 8420.

LCM(8400,8420) = 2⁴ × 3¹ × 5² × 7¹ × 421¹
LCM(8400,8420) = 3536400