diff --git a/lib/browser/Bignum.js b/lib/browser/Bignum.js
index ff00b03..7ada158 100644
--- a/lib/browser/Bignum.js
+++ b/lib/browser/Bignum.js
@@ -73,79 +73,38 @@ bnjs.prototype.toBuffer = function(opts) {
   return buf;
 };
 
-bnjs.prototype._add = _bnjs.prototype.add;
-
-bnjs.prototype.add = function(b) {
-  if (typeof b === 'number')
-    b = b.toString();
-  if (typeof b === 'number' || typeof b === 'string')
-    b = new _bnjs(b);
-  return this._add(b);
+function decorate(name) {
+  bnjs.prototype['_' + name] = _bnjs.prototype[name];
+  var f = function(b) {
+    if (typeof b === 'string')
+      b = new _bnjs(b);
+    else if (typeof b === 'number')
+      b = new _bnjs(b.toString());
+    return this['_' + name](b);
+  };
+  bnjs.prototype[name] = f;
 };
 
-bnjs.prototype._sub = _bnjs.prototype.sub;
-
-bnjs.prototype.sub = function(b) {
-  if (typeof b === 'number')
-    b = b.toString();
-  if (typeof b === 'number' || typeof b === 'string')
-    b = new _bnjs(b);
-  return this._sub(b);
-};
-
-bnjs.prototype._mul = _bnjs.prototype.mul;
-
-bnjs.prototype.mul = function(b) {
-  if (typeof b === 'number')
-    b = b.toString();
-  if (typeof b === 'number' || typeof b === 'string')
-    b = new _bnjs(b);
-  return this._mul(b);
-};
-
-bnjs.prototype._mod = _bnjs.prototype.mod;
-
-bnjs.prototype.mod = function(b) {
-  if (typeof b === 'number')
-    b = b.toString();
-  if (typeof b === 'number' || typeof b === 'string')
-    b = new _bnjs(b);
-  return this._mod(b);
-};
-
-bnjs.prototype._div = _bnjs.prototype.div;
-
-bnjs.prototype.div = function(b) {
-  if (typeof b === 'number')
-    b = b.toString();
-  if (typeof b === 'number' || typeof b === 'string')
-    b = new _bnjs(b);
-  return this._div(b);
-};
-
-bnjs.prototype._cmp = _bnjs.prototype.cmp;
-
-bnjs.prototype.cmp = function(b) {
-  if (typeof b === 'number')
-    b = b.toString();
-  if (typeof b === 'number' || typeof b === 'string')
-    b = new _bnjs(b);
-  return this._cmp(b);
-};
+decorate('add');
+decorate('sub');
+decorate('mul');
+decorate('mod');
+decorate('div');
+decorate('cmp');
 
 bnjs.prototype.gt = function(b) {
-  if (typeof b === 'number')
-    b = b.toString();
-  if (typeof b === 'number' || typeof b === 'string')
+  if (typeof b === 'string')
     b = new _bnjs(b);
+  else if (typeof b === 'number')
+    b = new _bnjs(b.toString());
   return this.cmp(b) > 0;
 };
 
 bnjs.prototype.lt = function(b) {
-  if (typeof b === 'number')
-    b = b.toString();
-  if (typeof b === 'number' || typeof b === 'string')
+  if (typeof b === 'string')
     b = new _bnjs(b);
+  else if (typeof b === 'number')
+    b = new _bnjs(b.toString());
   return this.cmp(b) < 0;
 };