The "Operator" Questions

" If A @ B means..."... 

We see this type of questions often. Two words: PLUG. IN. Just plug in the parameters (oops, I mean, numbers), and run (oops, I mean calculate) the function (oops, I mean the expression)!

1986 AJHSME Problem 11

1987 AJHSME Problem 21

1992 AJHSME Problem 6

1993 AJHSME Problem 9