In this worksheet, you must use the brackets buttons on your calculator.
Remember
The top and the bottom must go in brackets, so that:

= 

= 1 
The order of operations is
1. brackets
2. powers or indices
3. multiplication and division
4. adding and substraction
3 × 4^{2} = 3 × 16 = 48
and (3 × 4)^{2} = 12^{2} = 144
−5^{2} = −25 = (−(5 × 5))
(−5)^{2} = +25 = (−5) × (−5)