The left parenthesis symbol is used in combination with the right parenthesis symbol to group one or more expressions together. Parentheses are also used to represent multiplication and within the notation of a function. Typically parentheses are used in an expression like this:
In the expression above, the parentheses groups the expression 1 + 2 together so that the addition occurs before the multiplication. In plain language, this means add the numbers one and two together, then multiply the result by three. This changes the order of operations and produces a different result than if the parentheses were not there.