# Looking for 4-function calculators that know order of operations.

#### WBahn

Joined Mar 31, 2012
29,175
A local homeschool team has made it to the National Science Olympiad next month. For some events they are allowed to use a four-function (or five-function that includes sqrt) calculator and it would be very useful if that calculator applied order of operations. I don't know of any that do. Does anyone here know of one? A brand name and model would be most appreciated -- a link to where it can be purchased would be great. It has to be a physical calculator, so please don't suggest online calculators or phone apps.

TIA

#### crutschow

Joined Mar 14, 2008
32,932
it would be very useful if that calculator applied order of operations.
Do you mean it uses parentheses?

#### WBahn

Joined Mar 31, 2012
29,175
Do you mean it uses parentheses?
No. There can't be parentheses keys as those would be considered more than a four-function calculator.

I mean that if you enter the following:

1 * 2 + 3 * 4 + 5 * 6 =

The answer that will be returned is 44 because the calculator applies the rule that multiplication takes precedence over addition, so this is performed as

(1 * 2) + (3 * 4) + (5 * 6) = 44

This is what will happen on virtually every scientific calculator, because they are aware of order of operations.

But every four-function calculator I have ever used is not, so this would be evaluated left to right (i.e., the calculator only keeps a single running total that is updated every time a new operation key is pressed) as:

((((1 * 2) + 3) * 4) + 5) * 6 = 150

#### WBahn

Joined Mar 31, 2012
29,175
It would be ideal if there were a 4-function RPN calculator, but I doubt that was ever the case.

#### crutschow

Joined Mar 14, 2008
32,932
Some of the 4-function calculators have a GT (Grand Total) key which can help with such equations.
Example here.
Of course you still have to parse the equation manually for proper input.