To solve these expressions you have to apply the order of operations known as PEMDAS which stands for Parentheses, Exponent Multiplication/Division, Addition/Subtraction.→ first solve the terms on parentheses, then the exponents, then the multiplications/divisions and finally the aditions or subtractions.
1.

The Division must be solve first:

Next solve the subtraction

2.

First operation to solve is the multiplication:

Next solve the addition

3.

First solve the division

Then solve the multiplication
