diff --git a/source/Ox/js/Math.js b/source/Ox/js/Math.js
index 8b43d9ea..8ae31831 100644
--- a/source/Ox/js/Math.js
+++ b/source/Ox/js/Math.js
@@ -159,7 +159,7 @@ Ox.sign <f> Returns the sign of a number (-1, 0 or 1)
     1
 @*/
 Ox.sign = function(x) {
-    return x !== x || x === 0 ? x : x < 0 ? -1 : 1;
+    return x !== x || x === 0 ? +x : x < 0 ? -1 : 1;
 };
 
 /*@