Rules for removing brackets: put a+sign in front of brackets. After removing brackets, all symbols in brackets remain unchanged, and put a-sign in front of brackets. After removing brackets, all symbols in brackets change signs.

Parenthesis rule:+Before parentheses, all symbols in parentheses remain unchanged after parentheses, while-Before parentheses, all symbols in parentheses change sign after parentheses.

Let's see what others say.