This teacher gives me anxiety

I don’t understand. :(

The math problem is strictly talking about fractions, that is, which fraction is larger than the other. 5/6 IS bigger than 4/6, but the story surrounding the fractions implies that Marty's pizza is bigger than Luis's, however, that's not what the math problem is asking for. It's asking for "it's impossible for 4\6 to be larger than 5/6." Essentially, it isn't asking for a logical answer surrounding the story, rather, the logic of the numbers themselves. The teacher is advocating the misuse of the wording, and hence, the child was probably confused about how they got the answer wrong. These kind of problems and the teachers presenting them create improper logic thinking for children. So, although Marty's pizza WOULD be larger in real life, because he ate more with a smaller fraction, the word problem isn't looking for the real-world solution.