What is the Greatest Common Factor of 1978 and 1990?

Greatest common factor (GCF) of 1978 and 1990 is 2.

GCF(1978,1990) = 2

We will now calculate the prime factors of 1978 and 1990, than find the greatest common factor (greatest common divisor (gcd)) of the numbers by matching the biggest common factor of 1978 and 1990.

How to find the GCF of 1978 and 1990?

We will first find the prime factorization of 1978 and 1990. After we will calculate the factors of 1978 and 1990 and find the biggest common factor number .

Step-1: Prime Factorization of 1978

Prime factors of 1978 are 2, 23, 43. Prime factorization of 1978 in exponential form is:

1978 = 2¹ × 23¹ × 43¹

Step-2: Prime Factorization of 1990

Prime factors of 1990 are 2, 5, 199. Prime factorization of 1990 in exponential form is:

1990 = 2¹ × 5¹ × 199¹

Step-3: Factors of 1978

List of positive integer factors of 1978 that divides 1978 without a remainder.

1, 2, 23, 43, 46, 86, 989

Step-4: Factors of 1990

List of positive integer factors of 1990 that divides 1978 without a remainder.

1, 2, 5, 10, 199, 398, 995

Final Step: Biggest Common Factor Number

We found the factors and prime factorization of 1978 and 1990. The biggest common factor number is the GCF number.
So the greatest common factor 1978 and 1990 is 2.

Also check out the Least Common Multiple of 1978 and 1990