Solutions by » GCF of two numbers

What is the GCF of 55 and 51?

The GCF of 55 and 51 is 1.

Steps to find GCF

  1. Find the prime factorization of 55
    55 = 5 × 11
  2. Find the prime factorization of 51
    51 = 3 × 17
  3. To find the GCF, multiply all the prime factors common to both numbers:

    Therefore, GCF = 1

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The greatest common factor (GCF) is also known as greatest common divisor (GCD) or highest common factor (HCF).