# Problems with Calculator Syntax

## Have you ever borrowed someone else's calculator only to find that it just doesn't seem to work at all? That you can't even get it to perform the simplest calculations?

**The secret is that different calculators use different syntaxes**
('syntax' refers to the rules about the order you need to enter the information, just as there are rules about
the order of a grammatically correct sentence).

**Calculator Syntax**: For example, a common syntax is known as calculator syntax, in which you enter a number, an operator to apply (like '+'), and then the next number. Most people are used to this kind of calculator syntax, and would enter 2 + 3 = to get the expected answer of 5.

2 + 3 = → 5

**Algebraic Syntax**: A more complex syntax known as algebraic syntax considers precedence, or priority, of operators. For example, entering 2 + 3 x 6 would yield 30 under calculator syntax, but only 20 under algebraic syntax. The reason for this difference is that under algebraic syntax, 'x' has a higher priority than '+', so the calculator would first apply the 'x', yielding 2 + 18 = 20. Of course, this does require you to see the whole equation first, so you don't jump the gun and immediately calculate the 2 + 3 part.

2 + 3 x 6 = → 20

**Tenkey Syntax**: Accountants commonly use paper-tape adding machines, often called 'tenkeys', which use yet another syntax. Under this tenkey syntax, you enter a number, then its sign, with an assumption that you are summing all the numbers. So entering 5+ 3- 2- yields 0.

2 + 3 + → 5

**RPN Syntax**: RPN (Reverse Polish Notation) or scientific syntax is yet another type of calculator syntax. Under RPN syntax, you enter the numbers, then the operator that acts on both. So to go back to our first example, you'd type 2 Enter 3 Enter + to get the expected answer of 5. This can take a little planning when you have a lot of subexpressions.

2 E 3 E + → 5

There are other syntaxes, and we've barely scratched the surface of the ones above. Some people swear to the advantages of a particular syntax, but some good advice is to simply stick with the syntax you already know, and make sure a calculator you are going to purchase supports it. Here are a couple of examples:

- Calculator syntax: Canon LS-82Z Calculator
- Algebraic syntax: Texas Instruments TI-89 Graphing Calculator
- Tenkey syntax: Sharp CS-2635H Adding Machine
- RPN syntax: HP 35S Scientific Calculator

A few calculators support multiple syntaxes: Judy's TenKey for Windows is one, supporting calculator, tenkey, and RPN syntax ... and it actually goes a step further, letting you use an editable tape that recalculates whenever you make changes, regardless of the syntax you have selected. Judy's TenKey also has an extensive help system that more deeply explains each of these syntaxes, and their special extras. Judy's TenKey's greatest claim to fame is its editable tape that automatically recalculates whenever you make a change, and its multi-level undo (great for when you make a mistake in one of these more complicated equations and don't want to have to start over).