Depending on where commas are inserted, the sentence can state that three or four people love computers. In expressions with more than one operation, grouping symbols such as parentheses or division bars are often used to indicate the order in which to do the operations. These grouping symbols can change the meaning of an expression, just as commas or other punctuation marks can change the meaning of a sentence. In mathematics, more than in some other forms of written expression, ambiguity must be eliminated. Otherwise, different people may assign different meanings to the same symbols, and communication is faulty.
Ambiguity is eliminated using grouping symbols and the order of operations rule.
It should be pointed out to students that people communicate with computers by using programs. Programs tell the computer what to do. However, it is not always necessary for a person to be able to write a program in order to use a computer. Programs can be written in such a way that an operator can use them by answering a series of questions that are written into the program. Nevertheless, the best way to learn what a computer can and cannot do is to learn a little about programming.