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

Greatest Common Factor of 18 and 42

Make use of GCF Calculator to quickly find the Greatest Common Factor of numbers 18, 42 i.e. 6 largest integer by which both the numbers can be divided.

Greatest common factor (GCF) of 18 and 42 is 6.

GCF(18,42) = 6

GCF of 18 and 42

Greatest common factor or Greatest common divisor (GCD) can be calculated in following way;

GCF of:
and

Greatest Common Factor of 42 and 18 by Prime factorization method

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 18


2 18
3 9
3 3
1

Prime factors of 18 are 2,3. Prime factorization of 18 in exponential form is:

18 = 21×32

∴ So by taking common prime factors GCF of 42 and 18 is 6

Greatest Common Factor of 42 and 18 by matching factors method

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 18

List of positive integer factors of 18 that divides 18 without a remainder.

1,2,3,6,9,18

Greatest Common Factor

We found the factors and prime factorization of 42 and 18. The biggest common factor number is the GCF number.
So the greatest common factor 42 and 18 is 6.

Also check out the Least Common Multiple of 42 and 18

Properties of GCF 42 and 18

(i) The GCF of 42 and 18 is associative

GCF of 42 and 18 = GCF of 18 and 42

Frequently Asked Questions on GCF of 42 and 18

1. What is the GCF of 42 and 18?

Answer: GCF of 42 and 18 is 6.

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 18?

Answer: Factors of 18 are 1, 2, 3, 6, 9, 18. There are 6 integers that are factors of 18. The greatest factor of 18 is 18.

4. How to Find the GCF of 42 and 18?

Answer:

Greatest Common Factor of 42 and 18 = 6

Step 1: Find the prime factorization of 42

42 = 2 x 3 x 7

Step 2: Find the prime factorization of 18

18 = 2 x 3 x 3

Step 3: Multiply those factors both numbers have in common in steps i) or ii) above to find the gcf:

GCF = 2 x 3 = 6

Step 4: Therefore, the greatest common factor of 42 and 18 is 6