> 10
> (+ 5 3 4)
> (- 9 1)
> (/ 6 2)
> (+ ( * 2 4) (- 4 6))
> (let ((a 1) (b 2)) (+ a b (* a b)))
> a
> (define a 3)
> a
> (define b (+ a 1))
> (+ a b (* a b))
> (= a b)
> (if (and (> b a) (< b (* a b))) b a)
> (cond ((= a 4) 6) ((= b 4) (+ 6 7 a)) (else 25))
> (same-values? = new.= 3 1) #t > (same-values? < > 2 3) #f