One book has 84 pages. another book has 210 pages. which is the greatest common factor of the number of pages in the two books?

The greatest common factor, also referred to as the GCF, is the number that is able to divide the numbers in the set without remainder. We can calculate for the greatest common factor by first completely factoring out the numbers.

Factoring totally 84:

84 = 2 x 2 x 7 x 3

Factoring totally 210:

210 = 2 x 5 x 7 x 3

From the factoring done for both numbers, the common factors between the two are 2, 7, 3. Thus, the GCF is the product of these numbers which is equal to 42.

Hence, the answer is equal to 42.