Created By : Jatin Gogia
Reviewed By : Rajasekhar Valipishetty
Last Updated : Apr 06, 2023
Free LCM Calculator determines the least common multiple (LCM) between 42 and 56 the smallest integer that is 168 that is divisible by both numbers.
Least Common Multiple (LCM) of 42 and 56 is 168.
LCM(42,56) = 168
Least common multiple or lowest common denominator (LCD) can be calculated in three ways;
Least common multiple can be found by multiplying the highest exponent prime factors of 42 and 56. First we will calculate the prime factors of 42 and 56.
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 56
2 | 56 |
2 | 28 |
2 | 14 |
7 | 7 |
1 |
Prime factors of 56 are 2,7. Prime factorization of 56 in exponential form is:
56 = 23×71
Now multiplying the highest exponent prime factors to calculate the LCM of 42 and 56.
LCM(42,56) = 23×31×71
LCM(42,56) = 168
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 56
List of positive integer factors of 56 that divides 56 without a remainder.
1, 2, 4, 7, 8, 14, 28, 56
The formula of LCM is LCM(a,b) = ( a × b) / GCF(a,b).
We need to calculate greatest common factor 42 and 56, than apply into the LCM equation.
GCF(42,56) = 14
LCM(42,56) = ( 42 × 56) / 14
LCM(42,56) = 2352 / 14
LCM(42,56) = 168
(i) The LCM of 56 and 42 is associative
LCM of 42 and 56 = LCM of 56 and 42
1. What is the LCM of 42 and 56?
Answer: LCM of 42 and 56 is 168.
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 56?
Answer: Factors of 56 are 1, 2, 4, 7, 8, 14, 28, 56. There are 8 integers that are factors of 56. The greatest factor of 56 is 56.
4. How to Find the LCM of 42 and 56?
Answer:
Least Common Multiple of 42 and 56 = 168
Step 1: Find the prime factorization of 42
42 = 2 x 3 x 7
Step 2: Find the prime factorization of 56
56 = 2 x 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 = 168 = 2 x 2 x 2 x 3 x 7
Step 4: Therefore, the least common multiple of 42 and 56 is 168.