Euclid's Division Lemma Prime Factorisation Calculator Factors of a Number Calculator LCM Calculator GCF Calculator Factor Tree Calculator LCM of Decimals LCM of Fractions GCF of Decimals GCF of Fractions

Least Common Multiple of 28 and 42

Free LCM Calculator determines the least common multiple (LCM) between 28 and 42 the smallest integer that is 84 that is divisible by both numbers.

Least Common Multiple (LCM) of 28 and 42 is 84.

LCM(28,42) = 84

LCM of 28 and 42

Least common multiple or lowest common denominator (LCD) can be calculated in three ways;

LCM of:
and

Least Common Multiple (LCM) of 42 and 28 with Primes

Least common multiple can be found by multiplying the highest exponent prime factors of 42 and 28. First we will calculate the prime factors of 42 and 28.

Prime Factorization of 42


2 42
3 21
7 7
1

Prime factors of 42 are 2, 3,7. Prime factorization of 42 in exponential form is:

42 = 21×31×71

Prime Factorization of 28


2 28
2 14
7 7
1

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 42 and 28.

LCM(42,28) = 22×31×71
LCM(42,28) = 84

Factors of 42

List of positive integer factors of 42 that divides 42 without a remainder.

1, 2, 3, 6, 7, 14, 21, 42

Factors of 28

List of positive integer factors of 28 that divides 28 without a remainder.

1, 2, 4, 7, 14, 28

Least Common Multiple of 42 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 42 and 28, than apply into the LCM equation.

GCF(42,28) = 14
LCM(42,28) = ( 42 × 28) / 14
LCM(42,28) = 1176 / 14
LCM(42,28) = 84

Least Common Multiple of 42 and 28 by Listing Multiples

Multiples of 42

42,84

Multiples of 28

28, 56,84

Find the smallest number that is on all of the lists. We have it in bold above.

∴ Least Common Multiple of 42 and 28 is 84

Properties of LCM 42 and 28

(i) The LCM of 28 and 42 is associative

LCM of 42 and 28 = LCM of 28 and 42

Frequently Asked Questions on LCM of 42 and 28

1. What is the LCM of 42 and 28?

Answer: LCM of 42 and 28 is 84.

2. What are the Factors of 42?

Answer: Factors of 42 are 1, 2, 3, 6, 7, 14, 21, 42. There are 8 integers that are factors of 42. The greatest factor of 42 is 42.

3. What are the Factors of 28?

Answer: Factors of 28 are 1, 2, 4, 7, 14, 28. There are 6 integers that are factors of 28. The greatest factor of 28 is 28.

4. How to Find the LCM of 42 and 28?

Answer:

Least Common Multiple of 42 and 28 = 84

Step 1: Find the prime factorization of 42

42 = 2 x 3 x 7

Step 2: Find the prime factorization of 28

28 = 2 x 2 x 7

Step 3: Multiply each factor the greater number of times it occurs in steps i) or ii) above to find the lcm:

LCM = 84 = 2 x 2 x 3 x 7

Step 4: Therefore, the least common multiple of 42 and 28 is 84.