What is the GCF of 84 and 90?
Greatest Common Factor of 84 and 90 is the greatest possible number which divides both 84 and 90 exactly.
Answer: GCF of 84 and 90 is 6.
GCF of 84 and 90 will the largest number that divides 28 and 56 completely, without leaving a remainder.
Explanation
Method 1: GCF of 84 and 90 by Prime Factorisation Method
Prime Factorisation of 90: 2 × 3 × 3 × 5
Prime Factorisation of 84: 2 × 2 × 3 × 7
Common Factors of 24 and 84 are 2 and 3.
Hence, the greatest common factor of 84 and 90 = 2 × 3 = 6
Method 2: GCF of 84 and 90 by Long Division

Step 1: Divide the larger number 90 by the smaller number 84 and check the remainder. Here, the remainder is 6.

Step 2: Make the remainder 6 as the divisor and the divisor 84 as the dividend and perform the long division again.

Step 3: Continue till you get the remainder as 0 and the last divisor obtained is the GCF of 84 and 90.
You can find the GCF of 84 and 90 in any of the above methods but the solution will be the same.