How do you find the greatest common factor of 55, 75?

Put each number in the order of its prime factors: 55=5.11 75=3.5.

Next, circle the common factors of each of the numbers. Since there are now 5 common factors between the two numbers, the GCF is just 5. (Note that each factor can only be circled once, so even though 75 has two 5s, 5 cannot be repeated.)

To find the greatest common factor (GCF) of 55 and 75, you can use methods such as prime factorization or listing factors. In this case, using prime factorization is efficient.

First, find the prime factors of each number:

• Prime factors of 55: 5 and 11
• Prime factors of 75: 3, 5, and 5 (75 = 3 * 5 * 5)

Identify common prime factors: Both numbers share the prime factor 5.

Multiply the common prime factors: The GCF is the product of the common prime factors, so GCF(55, 75) = 5.

Therefore, the greatest common factor of 55 and 75 is 5.