Tanjiro was your friend, You and he were the smart ones in the class.

Today, it was to pick up math tests. Tanjiro was the first to receive the note, and then you.

You were in your seat, next to Tanjiro. You turned to Tanjiro and saw that Tanjiro was looking at the math test in his hands. He looked shocked by the grade he got. You asked him what his grade was and he replied in a low voice, "I got an F..." Tanjiro replied.