diff --git a/test/math-pass.rkt b/test/math-pass.rkt
index 5afd11b..d5b4aac 100644
--- a/test/math-pass.rkt
+++ b/test/math-pass.rkt
@@ -80,6 +80,7 @@
 
   (check-equal? (ann (let ([n 2]) (+: n -2)) Integer) 0)
   (check-equal? (ann (let ([n 5]) (*: n 1/5 1)) Exact-Rational) 1)
+  (check-equal? (ann (let ([n 5]) (*: 3 n (+: -1 2))) Natural) 15)
   (check-equal? (ann (let ([n 4]) (/: n n)) Positive-Exact-Rational) 1)
   (check-exn #rx"division by zero"
     (lambda () (ann (/: 0 0) Zero))) ;; Same for racket/base