RPN stands for Reversed Polish Notation. In this way of noting formulas, there is no need for use of "{[( )]}". There is also no need for the "=" sign. This sounds strange, but is easier than it looks in the beginning.

Just imagine you have to calculate 1250+2300+1.25+9-2500= ...

On paper you would write

1250

2300 +

1.25 +

9 +

2500 -

1060,25

You will use the "Enter" key only after the first entry (1250) to start calculating.

On a "normal" calculator you would finish this with the "=" key. After this, you cannot add other numbers, without retyping the last result. On a RPN Calculator, you would simply continue the operations as if you never ended them!

Also if you need to calculate ((1250+26)*6)/25)+100 = , you need to use "(" on the "standard" calculator. On a RPN calculator, simply key in the values you need, with the priority they have:

1250

26 +

6 *

25 /

100 +

Result 406,24. No need for "(" or other keys to separate block of a formula! Try it and you soon be addicted to RPN !