window.Calculator = {
  current: 0,
  add: function(inputFloat) {
    this.current += inputFloat;
    return this.current;
  }
};
window.Calculator = {
  current: 0,
  add: function(inputArray) {
    var sum = this.current;
    var i;
    for(i = 0, len = arguments.length; i< len; i++) {
      sum += arguments[i];
    }
    this.current = sum;
    return this.current;
  }
};
add method is now able to take multiple numbers as inputs