#lang typed/racket
(: multiple-of-3-or-5? (-> Integer Boolean))
(define [multiple-of-3-or-5? α]
[or [zero? [modulo α 3]]
[zero? [modulo α 5]]])
(: test-run (-> Integer Integer Integer))
(define (test-run i ret)
(cond ((>= i 10000000) ret)
(else (test-run (+ 1 i) (if (multiple-of-3-or-5? i) (+ ret i) ret)))))
(display "The sum is:")
(display (test-run 0 0))
(newline)
