diff --git a/es6-shim.js b/es6-shim.js
index d1d052fe..ae10e83d 100644
--- a/es6-shim.js
+++ b/es6-shim.js
@@ -1179,14 +1179,13 @@
       var NumberShim = function Number(value) {
         var primValue = Type.primitive(value) ? value : toPrimitive(value, 'number');
         if (typeof primValue === 'string') {
+          primValue = _call(trimShim, primValue);
           if (isBinary(primValue)) {
             primValue = parseInt(_strSlice(primValue, 2), 2);
           } else if (isOctal(primValue)) {
             primValue = parseInt(_strSlice(primValue, 2), 8);
           } else if (hasNonWS(primValue) || isBadHex(primValue)) {
             primValue = NaN;
-          } else {
-            primValue = _call(trimShim, primValue);
           }
         }
         var receiver = this;
diff --git a/test/number.js b/test/number.js
index c6276f13..7b7fa204 100644
--- a/test/number.js
+++ b/test/number.js
@@ -380,8 +380,17 @@ describe('Number', function () {
 
     it('works with binary literals in string form', function () {
       expect(Number('0b1')).to.equal(1);
+      expect(Number(' 0b1')).to.equal(1);
+      expect(Number('0b1 ')).to.equal(1);
+
       expect(Number('0b10')).to.equal(2);
+      expect(Number(' 0b10')).to.equal(2);
+      expect(Number('0b10 ')).to.equal(2);
+
       expect(Number('0b11')).to.equal(3);
+      expect(Number(' 0b11')).to.equal(3);
+      expect(Number('0b11 ')).to.equal(3);
+
       expect(Number({ toString: function () { return '0b100'; }, valueOf: function () { return '0b101'; } })).to.equal(5);
     });