Math.round = function(number) {
  return number*10%10<5 ? Math.floor(number) : Math.ceil(number);
};

Math.floor = function(number) {
  return ((number*10) - (number*10%10))/10;
};

Math.ceil = function(number) {
  return ((number*10) - (number*10%10))/10 + 1; // TODO: fix this
};