(+ 2 2)
4
(* 3 5)
15
(/ 10 2)
5
(- 15 5 3 2)
5
(* (+ 2 2) (- 4 3))
4
(boolean? #t)
#t
(boolean? (+ 2 2))
#f
(string? "hello")
#t
(string? (* 3 2))
#f