((3 + 4) * 9 - 2 * 3)?
A: It is as though the expression were fully
parenthesized as:
(((3 + 4) * 9) - (2 * 3)) = 57
Q: Why this parenthesization, and not some
other one, like:
((3 + 4) * (9 - (2 * 3))) = 21 ?
A: Because of the precedence rules of arithmetic: