Confuse the Boy

Daelyn: "Why doesn't Mrs. Routhier teach Sissy anymore?"

Me: "Because Mrs. Routhier teaches third grade."

Daelyn: "What grade is Sissy in?"

Me: "Fourth grade."

Daelyn: "Next year, will Mrs. Routhier teach her again?"

Me: "No, Daelyn, Mrs. Routhier already taught Sissy. Next year, she'll have a new teacher."

Daelyn: "Why is it called Fourth grade?"

Me: "Fourth for Four. What number does Third stand for?"

Daelyn: "I dunno."

Me: "Well, think, son. If Fourth grade is Grade Four, then Third grade is Grade what?"

D: "Four? No, two."

M: "Son, Third grade is Grade Three."

D, dully: "Oh."

M: "What comes after Fourth Grade?"

D, triumphantly: "Fifth!!"

M: "No! SUMMER!"