What is the GCF of 20 and 24?
GCF (Highest Common Factor) of two numbers is the greatest possible number which divides the two numbers exactly without any remainder.
Answer: GCF of 20 and 24 is 4
We will explain the GCF of 20 and 24 using the following two methods.
Methods to find GCF of 20 and 24

Prime factorization Method

Long division Method
Method 1: GCF of 20 and 24 by Prime Factorization
Let us express 20 and 24 as a product of its prime factors
Prime factorization of 20 is 2 × 2 × 5
Prime factorization of 24 is 2 × 2 × 2 × 3
Common factors = 2, 2
GCF is the product of the prime factors that are common to the prime factorization of 20 and 24
GCF of 20 and 24 is 4
Method 2: GCF of 20 and 24 by Long Division

Step 1: Divide the largest number 24 by the smaller number 20 and check the remainder.

Step 2: Make the remainder of the above step as the divisor and the divisor of the above step as the dividend and perform the long division again.

Step 3: Continue till you get remainder as 0 and GCF of 20 and 24 is the last divisor obtained.
You can find the GCF of 20 and 24 in any of the above methods but the solution will be the same.