This document provides instructions and explanations for using a graphing calculator correctly. It contains 4 examples of calculator expressions and the correct order of operations to arrive at the right answer. Parentheses are important to specify the proper order when multiple operations are involved. The subtract key is also important to use rather than a negative sign for subtraction problems. Forgetting parentheses in the denominator of a fraction can lead to an incorrect solution.

1. MAT 150
Graphing Calculator
Activity
Work through the following slides to see how well
you know how to use the graphing calculator.

2. 1) Which of the following two calculator screens will yield the
correct answer for:
5 7
6 3

3. The correct answer is:
Because when you don’t use parenthesis the
calculator misinterprets what you are wanting to do.
Without the parenthesis the calculator thinks you
want to add 5 to 7/6 and then subtract 3 instead of
adding 5 and 7 and subtracting 6 and 3, then divide
the two numbers. The calculator needs the
parenthesis to tell it the exact order to perform the
operations.

4. 2) Which of the following two calculator screens will yield the
correct answer for:
2/3
125

5. The correct answer is:
Because when you don’t use parenthesis the
calculator misinterprets what you are wanting to do.
Without the parenthesis the calculator thinks you
want to square 125 and then divide that answer by 3,
Instead of raising 125 to the two thirds power. The
calculator needs the parenthesis to tell it the exact
order to perform the operations.

6. 3) Which of the following two calculator screens will yield the
correct answer for:
4 5

7. The correct answer is:
Because when you don’t use the subtract key, on the
right side of your calculator, and use the negative sign,
on the bottom of your calculator instead, it
misinterprets what you are wanting to do. If you use
the negative sign it thinks you want to take 4 times
negative 5 instead of 4 minus 5. The calculator needs
you to use the correct symbol in order to perform the
operations you want.

8. 4) Now try finding the correct answer to the following using
your calculator.
6(5 7)
4 (8 3)5

9. The correct answer is: -0.41379… not 22
If you got 22 for an answer you most likely forgot your
parenthesis for the whole denominator.