Correct Answer, Stands Corrected

(I am in math class, and we are learning about a formula. The teacher asks a question that can be solved with the formula.)

Teacher: “Who can solve the problem using [Mathematician]’s Rule? [Classmate]?”

Classmate: *says the correct answer*

Teacher: “Correct! See, [Classmate] is almost as smart as [Mathematician]!”

Classmate: “Who’s [Mathematician]?”

Teacher: “Never mind.”