5.5.3 Role of Parentheses
Now we’ll investigate why parentheses need to be placed around negative numbers.
Let’s check what happens if you square −5. When you multiply a negative number by a negative number, the answer is positive. So, if you want to find the square of −5, you calculate and the answer is 25.
The calculator can be accessed on the left-hand side bar under Toolkit.
Activity: Squaring −5
Use the calculator to find .
Remember that negative numbers must be enclosed in parentheses.
You should indeed have found that . The calculator screen looks like this:
Activity: Forgotten Parentheses
Now let’s suppose that you forget the rule about enclosing negative numbers in parentheses and you enter with no parentheses. NOTE: You will have to do this using your keyboard because the calculator does not allow negative numbers created with the button to be entered without parentheses.
Use the keyboard and type in − 5 ^ 2, then hit the return key. What happens?
Remember that you may have to clear the calculator by clicking on before you can begin typing. Also, do NOT use the button—use your keyboard.