What is the Least Common Multiple of 1280 and 1285?

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 1280 and 1285 with GCF Formula

The formula of LCM is LCM(a,b) = ( a × b) / GCF(a,b).
We need to calculate greatest common factor 1280 and 1285, than apply into the LCM equation.

GCF(1280,1285) = 5
LCM(1280,1285) = ( 1280 × 1285) / 5
LCM(1280,1285) = 1644800 / 5
LCM(1280,1285) = 328960

Least Common Multiple (LCM) of 1280 and 1285 with Primes

Least common multiple can be found by multiplying the highest exponent prime factors of 1280 and 1285. First we will calculate the prime factors of 1280 and 1285.

Prime Factorization of 1280

Prime Factorization of 1285

Now multiplying the highest exponent prime factors to calculate the LCM of 1280 and 1285.

LCM(1280,1285) = 2⁸ × 5¹ × 257¹
LCM(1280,1285) = 328960