Created By : Jatin Gogia
Reviewed By : Rajasekhar Valipishetty
Last Updated : Apr 06, 2023
Free LCM Calculator determines the least common multiple (LCM) between 4 and 20 the smallest integer that is 20 that is divisible by both numbers.
Least Common Multiple (LCM) of 4 and 20 is 20.
LCM(4,20) = 20
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 4 and 20. First we will calculate the prime factors of 4 and 20.
Prime Factorization of 4
2 | 4 |
2 | 2 |
1 |
Prime factors of 4 are 2. Prime factorization of 4 in exponential form is:
4 = 22
Prime Factorization of 20
2 | 20 |
2 | 10 |
5 | 5 |
1 |
Prime factors of 20 are 2,5. Prime factorization of 20 in exponential form is:
20 = 22×51
Now multiplying the highest exponent prime factors to calculate the LCM of 4 and 20.
LCM(4,20) = 22×51
LCM(4,20) = 20
Factors of 4
List of positive integer factors of 4 that divides 4 without a remainder.
1, 2, 4
Factors of 20
List of positive integer factors of 20 that divides 20 without a remainder.
1, 2, 4, 5, 10, 20
The formula of LCM is LCM(a,b) = ( a × b) / GCF(a,b).
We need to calculate greatest common factor 4 and 20, than apply into the LCM equation.
GCF(4,20) = 4
LCM(4,20) = ( 4 × 20) / 4
LCM(4,20) = 80 / 4
LCM(4,20) = 20
(i) The LCM of 20 and 4 is associative
LCM of 4 and 20 = LCM of 20 and 4
1. What is the LCM of 4 and 20?
Answer: LCM of 4 and 20 is 20.
2. What are the Factors of 4?
Answer: Factors of 4 are 1, 2, 4. There are 3 integers that are factors of 4. The greatest factor of 4 is 4.
3. What are the Factors of 20?
Answer: Factors of 20 are 1, 2, 4, 5, 10, 20. There are 6 integers that are factors of 20. The greatest factor of 20 is 20.
4. How to Find the LCM of 4 and 20?
Answer:
Least Common Multiple of 4 and 20 = 20
Step 1: Find the prime factorization of 4
4 = 2 x 2
Step 2: Find the prime factorization of 20
20 = 2 x 2 x 5
Step 3: Multiply each factor the greater number of times it occurs in steps i) or ii) above to find the lcm:
LCM = 20 = 2 x 2 x 5
Step 4: Therefore, the least common multiple of 4 and 20 is 20.