diff --git a/2_78.rkt b/2_78.rkt
index 025a69f..2f6dc68 100644
--- a/2_78.rkt
+++ b/2_78.rkt
@@ -342,8 +342,11 @@
 
 (define (scheme-number->complex n)
   (make-complex-from-real-imag (contents n) 0))
+(define (scheme-number->rational n)
+  (make-rational n 1))
 
 (put-coercion 'scheme-number 'complex scheme-number->complex)
+(put-coercion 'scheme-number 'rational scheme-number->rational)
 
 (define (scheme-number->scheme-number n) n)
 (define (complex->complex z) z)