<span>The GCF is the number that is a factor of both (or all) of the numbers of a given set and which is the biggest factor of this kind (often the smaller number of the two)
7 and 14 have a greatest common factor of 7.
28 and 7 also have a GCF of 7, so the first two responses fit.
21 and 3 have a GCF of 3, so that isn't correct.
7 and 1 have a GCF of 1, so that's incorrect as well.</span>
Longest book: 396 Shortest book: 1/4×396=99 Middle book: 3×99= 297 <span> If the book in the middle of her shelf has three times the number of pages of the shortest book then how many pages does the middle book have? Answer: 297</span>
