diff --git a/tokenize.js b/tokenize.js
index d04c61d..7775a15 100755
--- a/tokenize.js
+++ b/tokenize.js
@@ -13,10 +13,7 @@ function isDigit(c) {
   if (isNaN(code)) {
     return false;
   }
-  return (46 < code &&
-          code < 58 ||
-          code < 58 &&
-          code > 46);
+  return (47 < code && code < 58);
 }
 
 function isWhitespace(c) {