What is the Least Common Multiple of 1905 and 1920?

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 1905 and 1920 with GCF Formula

The formula of LCM is LCM(a,b) = ( a × b) / GCF(a,b).
We need to calculate greatest common factor 1905 and 1920, than apply into the LCM equation.

GCF(1905,1920) = 15
LCM(1905,1920) = ( 1905 × 1920) / 15
LCM(1905,1920) = 3657600 / 15
LCM(1905,1920) = 243840

Least Common Multiple (LCM) of 1905 and 1920 with Primes

Least common multiple can be found by multiplying the highest exponent prime factors of 1905 and 1920. First we will calculate the prime factors of 1905 and 1920.

Prime Factorization of 1905

Prime Factorization of 1920

Now multiplying the highest exponent prime factors to calculate the LCM of 1905 and 1920.

LCM(1905,1920) = 3¹ × 5¹ × 127¹ × 2⁷
LCM(1905,1920) = 243840