The tutor points out a habit some people don’t realize they have, yet it nickels and dimes them out of marks. It often comes up during tutoring….

Consider the following expression:

Of course, we know this expression must equal 1:

How would you enter the expression above on a calculator? Some people might enter it as 2+6÷3+5, which will yield the answer 9 on many calculators. What’s the problem, and what can be done to get the answer one would expect?

Your typical scientific calculator will follow the order of operations (BEDMAS: brackets, exponents, division, multiplication, addition, subtraction). Receiving the expression

2+6÷3+5

the calculator does the division first: specifically, 6÷3=2:

2+2+5

then proceeds to the addition:

2+2+5=9

While some calculators have up-and-down display that shows fractions as people write them, most people I see don’t yet use those models. The one-line scientific calculator likely won’t know, if you enter 2+6÷3+5, that you mean

(if, in fact, that’s what you mean). It just follows BEDMAS.

How can you enter

so your scientific calculator will understand? Use brackets:

(2+6)÷(3+5)

Now, following BEDMAS, the calculator will execute the brackets first:

(2+6)÷(3+5)=8÷8

Next, it will divide:

8÷8=1

If you’re unsure, try some examples on your calculator to make sure your entry method gets the answers it should:)

Jack of Oracle Tutoring by Jack and Diane, Campbell River, BC.