What is the Least Common Multiple of 1985 and 1990?

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 1985 and 1990 with GCF Formula

The formula of LCM is LCM(a,b) = ( a × b) / GCF(a,b).
We need to calculate greatest common factor 1985 and 1990, than apply into the LCM equation.

GCF(1985,1990) = 5
LCM(1985,1990) = ( 1985 × 1990) / 5
LCM(1985,1990) = 3950150 / 5
LCM(1985,1990) = 790030

Least Common Multiple (LCM) of 1985 and 1990 with Primes

Least common multiple can be found by multiplying the highest exponent prime factors of 1985 and 1990. First we will calculate the prime factors of 1985 and 1990.

Prime Factorization of 1985

Prime Factorization of 1990

Now multiplying the highest exponent prime factors to calculate the LCM of 1985 and 1990.

LCM(1985,1990) = 5¹ × 397¹ × 2¹ × 199¹
LCM(1985,1990) = 790030