(define-syntax pr
  (syntax-rules ()
    ((_ x ...) (begin (display x) ... (newline)))))

(pr (modulo 13 4));                   ===>  1
(pr (remainder 13 4));                ===>  1

(pr (modulo -13 4));                  ===>  3
(pr (remainder -13 4));               ===>  -1

(pr (modulo 13 -4));                  ===>  -3
(pr (remainder 13 -4));               ===>  1

(pr (modulo -13 -4));                 ===>  -1
(pr (remainder -13 -4));              ===>  -1

(pr (number->string 33 10))
(pr (number->string 33 2))
(pr (number->string 33 8))
(pr (number->string 33 16))

(pr (number->string 33 10))
(pr (number->string 33.45 10))
(pr (number->string 1.2e-5 10))

(pr (string->number "123" 10))
(pr (let ((t::double (string->number "123.5" 10))) t::double))
(pr (string->number "123" 16))
(pr (+ 3 (string->number "123" 16)))
(pr (remainder (string->number "123.7" 16) 2)) ; returns int result
(pr (sin (string->number "123.5" 10)))