It reveals even as it conceals. A cross to the christian is could be a dead dumb piece of wood, yet filled with meaning, hope, numinous and transcendental images, which evoke love, passion, duty, hope and redemption. Defile a Koran or even a crescent on a piece of cloth and you can be dead within minutes of such an act in Sudan, or Iran, or Afghanistan. In the right context in Zanzibar, or Germany or Venezuela or Martinique one of these symbols can earn you a date, or an event in bed or an encounter with the police. You may even be killed by a jealous lover or husband or father.
Symbols are stuff of human life, all aspects of our lives.
Often the problem is that their teachers have fatal incompetence in Mathematics and Science. That is the tragedy of thousands of helpless people who are victims of ignorant, amoral and incompetent teachers, too many of them in our class rooms. They are mere symbols. There are rules governing the use of these symbols. This is the comutative property of addition.