Other than being obviously new, this is pretty cool.

Edit: Would there be a better way to fix it than to add functions like this?

  function adder() {
    var args = Array.prototype.slice.call(arguments);
    return args.reduce(function(a, b){return a + b})
  }

  function subtractor() {
    var args = Array.prototype.slice.call(arguments);
    return args.reduce(function(a, b){return a - b})
  }

  function multiplier() {
    var args = Array.prototype.slice.call(arguments);
    return args.reduce(function(a, b){return a * b})
  }

  function divider() {
    var args = Array.prototype.slice.call(arguments);
    return args.reduce(function(a, b){return a / b})
  }