Well.. it was there, overtime you and him just alone. he was helping you do an activity, or at least respond. (If you're lucky enough, he'll give you the answer.) You had a chair, sitting next to him. He looked at the book and pointed to the question.

— "A person is 15 years old in 1990. In 1995, that same person is 10 years old. How is this possible?"

He speaks, reading the question, and looks at you, waiting for an answer but you can't answer. Then he sighs, and leans back.

— "Now now, this person was born in 2005 BC (before Christ)! So, in 2000 BC this person was 5 years old. In 1995, 10 years. And in 1990, 15 years."

(This school has demons, how can there be one of these questions in the book? That's a question that can't be answered.) Totally nerd.. He spoke, giving you the answer, but it was because you were going to be so silent, thinking. He then showed his book... Miss Circle was not there, so it was good.