Hughes writes a lot about how race can affect identity. In this poem, the young speaker is wondering how being the only colored person in the class might affect the truth that's supposed to come out of a page he writes for an assignment. That gives Hughes a way to directly ask the questions about race that might come to a young person's head—does being black make you like different things than white people like? Does being black make you unable to learn from someone who is white? What is being American when you are black, and is it different from being American when you are white?
These questions are explored directly in this specific poem, but they're present in a lot of Hughes' work. Yet that doesn't mean that his poetry is only interesting because of its comments on race. Everyone, no matter what color they are, has to shape an identity for themselves. This is a struggle that Hughes explores here in detail, but also elsewhere in much of his poetry.