When there is a "+"in front of the bracket, remove the constant symbol in the bracket. Such as 5+(3+4)=5+3+4, 8+(7-3) = 8+7-3;

When there is a "-"in front of the bracket, remove the symbol in the bracket. Such as 8-(3+4)=8-3-4, 8-(7-3) = 8-7+3;

The rules of multiplication and division before parentheses should be learned later. The rules are as follows:

When there is an "×" in front of the bracket, remove the constant symbol in the bracket. For example, 5× (3× 4) = 5× 3+4, 8× (7÷3) = 8× 7÷ 3;

When "∫" comes before the bracket, remove the sign in the bracket. Such as 8÷(3×4)=8÷3÷4, 8 ÷ (7× 3) = 8 ÷ 7× 3;

I teach mathematics, hope to adopt it!