() {
		var a = 0;
		for (var i = 0, l = arguments.length; i < l; i++) {
			a = a + arguments[i];
		}
		return a;
	};
	/**************** 创建缓存代理的工厂 *****************/
	var createProxyFactory = function (fn) {
		var cache = {};
		return function () {
			var args = Array.prototype.join.call(arguments, ',');
			if (args in cache) {
				return cache[args];
			}
			return cache[args] = fn.apply(this, arguments);
		}
	};

	var proxyMult = createProxyFactory(mult),
		proxyPlus =