
Calculators use a variety of symbols to represent the mathematical operations. For example, some calculators have the symbol (±) rather than (−) to enter a negative number.
Calculators also vary on how they interpret "order of operations." There are three basic types:

PEMDAS: Use the conventional order of operations that is accepted in math.

Operation Activated: Each operation activates the equal key.

RPN: Reverse Polish Notation is used by some technical calculators.


Did you know that you can register your wireless phone number with the "National Do Not Call List" to protect yourself from sales calls? Visit the National Do Not Call Registry to learn more about how to avoid telephone solicitations.

Using the standard order of operations, you need to add the numbers in parentheses before dividing. So, (d) is a correct way to find the average.
Try confirming this by estimating the answer and then trying both ways with your calculator. The average of 50, 62, and 73 is about 60. Some calculators give $136.33 for (c) while all calculators give $61.67 for (d). The keystrokes for (d) are closest to the estimate, so (d) is a correct way to find the average.

Comments (3)
These comments are not screened before publication. Constructive debate about the information on this page is welcome, but personal attacks are not. Please do not post comments that are commercial in nature or that violate copyright. Comments that we regard as obscene, defamatory, or intended to incite violence will be removed. If you find a comment offensive, you may flag it.
When posting a comment, you agree to our Terms of Use.Showing 3 commentsRon Larson (author)10 years ago Thanks. I like this too. One of the great things about having the book online is that we have space to include more information, such as different key stroke sequences.0 0Guest 10 years ago I really like including the key strokes for the Calculator. I've been doing this when I lecture and students have responded positively. I capture my lecture videos with Camtasia and One Note, along with a TI Calculator on the desktop that saves key strokes. I then copy and past the key strokes into the notes so the students can view them after they are posted on Blackboard with the lecture video.0 0Ron Larson (author)10 years ago Notice that PEMDAS represents the standard order of operations, as in "Please Excuse My Dear Aunt Sally."0 0