The fifth graders were given sandwiches for lunch during their field trip. Nathan ate 5/6 of his sandwich, Leroy ate 7/8 of his sandwich, and Sofia ate 5/8 of her sandwich. Who ate the greatest amount of their sandwich?

The greatest amount is when the bottom part of the fraction (denominator) is almost as large as the top part of a fraction (numinator)

This means that even if 5/6 numbers are very similar to each other, that does not mean they are the biggest. The biggest denominator is 8 - however the numinator is 5 - so the difference between those numbers is quite big. This means that the person left is Leroy, who had almost the biggest denominator, and a similar nominator.

Nathan ate 20/24, Leroy ate 21/24, and Sofia ate 15/24 meaning Leroy ate the most