## Monday, October 30, 2006

### Which one is better? HP 12C or TI BA II Plus

This is an old post of mine, defending the virtue of HP 12C over TI BA II Plus. Hewlett Packard 12C and Texas Instrument BA II Plus are both the only type of calculator allowed in CFA exam.

One of the most significant differences between those two is the procedure to enter operation such as addition, substraction, multiplication, and division. HP 12C use what mathematician call postfix notation, where TI BA II Plus use infix notation.

The following example will illustrate both notations.
Example of problem to be solved: 2 x ( 3 + 5 ) =

The buttons to be pressed on infix calculator (TI BA II Plus) are:
"2","X","(","3","+","5",")","=". For a total of 8 buttons pressed.
Note that the button pressed are buttons pressed in so called "normal" calculator.

The buttons to be pressed on postfix calculator (HP 12C) are:
"2","Enter","3","Enter","5","+","X". For a total of 6 buttons pressed.

HP 12C is superior than TI BA II Plus for the following reasons:
1. In HP 12C, you dont have to remember the number of open or close parantheses outstanding because parantheses are not needed.
2. Consequently, mistakes in inputing paranthesis are eliminated.
3. The number of buttons to be pressed for an equation can be less.

The only barrier in choosing HP 12C over TI BA II Plus is that people are usually more used to the infix notation. But in my opinion, once you master the postfix notation, you will definitely choose it over infix notation.

Below is the link to a HP 12C if you decide to buy it. No, I'm not gonna give you the link to the more inferior calculator :-). Anonymous said...

Stupid example!

In TI you can do your example in 6 steps:
3
+
5
=
*
2

Now, do it in your HP: ((6/2)+5)*(3/(1+2))!

Amitz Sekali said...

You unfairly rearrange the sequence of number. Additionally, if they are 2 nested brackets, you will eventually have to rely on pressing '(' or ')' which mean more buttons pressed.

As for your example, 6 enter 2 / 5 + 3 enter 1 enter 2 + / * , for a total of 14 buttons in HP. Doing it in TI is ( ( 6 / 2 ) + 5 ) * ( 3 / ( 1 + 2 ) ) = , for a total of 20 buttons (or 19 if TI can calculate without =)!