GCF of 70 and 21

Number 1Number 2(Optional) Enter Number 3

Determine the Greatest Common Factor (GCF) of (70,21)

Determine the factors for 70 up to 21 since that is the minimum of the 2 numbers
1,2,5,7,10,14

Determine the factors for 21 up to 21 since that is the minimum of the 2 numbers
1,3,7,21

The common factors between them are 1,7
The greatest common factor between them is 7
Since the Greatest Common Factor of both numbers ≠ 1, the numbers are not relatively prime (co-prime)
Since the Greatest Common Factor of Both Numbers is both ≠ 1 and have a difference of two, the numbers are not twin prime
To see the LCM of these numbers, click the LCM button above