"Ji suan Ji"

My cousin was telling me something very funny bout my typical elder brother.You see, my bro's chinese is very bad, and this is how it goes.

Grandma:" Ks, you are taking what course(in chinese lar)?"(he's taking accountancy)
Bro:" ji suan ji."(calculator)
Grandma:"?" " kuai ji?"
At this point of time, my cousin and my lil sis were eating some fruit.(let's assume it be apple) They were suffering from stomach discomfort. cos of overboard laughters.
Me:"HAHAHAHAHAHAHAHAHAHAHAHAHAHAHAAHAHAHA"

damn funny right!? this is my bro's chinese man.