As addition is based upon the idea of combining groups of things to yield a larger group, subtraction, the opposite of addition, is based on the idea of removing objects from a group, thereby reducing its size. These intuitive ideas of combining and reducing were undoubtedly engrained in daily life for even the earliest humans. When numbers are used to represent the quantity of objects composing groups, subtraction becomes an operation upon those numbers. Indeed, subtraction is one of four fundamental arithmetic operations (the others being addition, multiplication, and division). The symbol that denotes subtraction is "-", read "minus". For instance, "A minus B" means that quantity B is to be subtracted from quantity A, where "A" is the minuend and "B" is the subtrahend. The word minus comes from the Latin word "minus", which means "less".

By calling subtraction an operation, it is meant that any number...