In some cases the question arises as to the order of operations. If an AND and an OR appear in the same expression, which is to be done first? The order of operations of Boolean Algebra are the same as standard algebra. The AND operation (same as multiplication) is performed first. Of course, parentheses can be used to alter the order of operations just as in standard algebra. In the expression AB + C, A is ANDed to B then ORed with C. In the expression, A(B + C), B is ORed with C first, then ANDed with A.
A function inside a parentheses must be accomplished first before any functions outside the parentheses. A bar over several variables can also act as a parentheses. Any function under the bar must be done before any functions not under the bar.