GCF for 4 and 20
What is the Greatest Common Divisor of 4 and 20?
Answer
(Four)
Finding GCF for 4 and 20 using all factors (divisors) listing
The first method to find GCF for numbers 4 and 20 is to list all factors for both numbers and pick the highest common one:
All factors of 4: 1, 2, 4
All factors of 20: 1, 2, 4, 5, 10, 20
So the Greatest Common Factor for 4 and 20 is 4
Finding GCF for 4 and 20 by Prime Factorization
The second method to find GCF for numbers 4 and 20 is to list all Prime Factors for both numbers and multiply the common ones:
All Prime Factors of 4: 2, 2
All Prime Factors of 20: 2, 2, 5
As we can see there are Prime Factors common to both numbers: 2, 2
Now we need to multiply them to find GCF: 2 × 2 = 4
Related Calculations
See Also
- Least Common Multiple - Find the Least Common Multiple (LCM) of two numbers
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GCF Table
About "Greatest Common Factor" Calculator
Greatest Common Factor (GCF) also known as the Greatest Common Divisor (GCD) or Highest Common Factor (HCF) - it is the largest positive integer that divides each of the integers with zero remainder.