What is the Least Common Multiple of 4 and 28?
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 4 and 28 is 28.
LCM(4,28) = 28
Least Common Multiple of 4 and 28 with GCF Formula
The formula of LCM is LCM(a,b) = ( a × b) / GCF(a,b).
We need to calculate greatest common factor 4 and 28, than apply into the LCM equation.
GCF(4,28) = 4
LCM(4,28) = ( 4 × 28) / 4
LCM(4,28) = 112 / 4
LCM(4,28) = 28
Least Common Multiple (LCM) of 4 and 28 with Primes
Least common multiple can be found by multiplying the highest exponent prime factors of 4 and 28. First we will calculate the prime factors of 4 and 28.
Prime Factorization of 4
Prime factors of 4 are 2. Prime factorization of 4 in exponential form is:
4 = 22
Prime Factorization of 28
Prime factors of 28 are 2, 7. Prime factorization of 28 in exponential form is:
28 = 22 × 71
Now multiplying the highest exponent prime factors to calculate the LCM of 4 and 28.
LCM(4,28) = 22 × 71
LCM(4,28) = 28