GCF for 42 and 84
What is the Greatest Common Divisor of 42 and 84?
Answer
(Forty-two)
Finding GCF for 42 and 84 using all factors (divisors) listing
The first method to find GCF for numbers 42 and 84 is to list all factors for both numbers and pick the highest common one:
All factors of 42: 1, 2, 3, 6, 7, 14, 21, 42
All factors of 84: 1, 2, 3, 4, 6, 7, 12, 14, 21, 28, 42, 84
So the Greatest Common Factor for 42 and 84 is 42
Finding GCF for 42 and 84 by Prime Factorization
The second method to find GCF for numbers 42 and 84 is to list all Prime Factors for both numbers and multiply the common ones:
All Prime Factors of 42: 2, 3, 7
All Prime Factors of 84: 2, 2, 3, 7
As we can see there are Prime Factors common to both numbers: 2, 3, 7
Now we need to multiply them to find GCF: 2 × 3 × 7 = 42
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.