RPN Calculator

Easy-to-use calculator for simple mathematical operations using powerful Reverse Polish Notation (RPN), like HP calculators as HP-48 series or HP-12C.


This app is ad-supported (that's the only purpose for which network access permission is used). If you prefer, a Premium version is also available with some additional buttons, no ads and no network access permission necessary.


Instructions
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The stack
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When you type a number and press Enter, the number is stored in the lowest position of the stack, marked by 1:

If you type another number and press Enter, the second number takes the lowest position, and the first number is pushed to position 2: (if you just press Enter without typing a new number, the first number is duplicated).

You can store up to 50 numbers in the stack, even though the screen only shows the numbers on the 4 lowest positions (1: to 4:)

If you press the Down arrow, the number in the lowest position in the stack is erased, and the others are popped one position down.

Press C to cancel the number while you are typing. Press C again to clear the stack.

Mathematical operations
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If you press one of the mathematical symbols (+,-,x,÷), the corresponding operation is executed using as operands the two numbers in the lowest positions of the stack.

If you press one of the mathematical symbols while typing a number, the operation is executed between the number in the lowest position of the stack and the number that you are currently typing.

The ± key will change the sign of the number that you are currently typing or that of the number in the lowest position of the stack otherwise.

Example
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If you want to compute the operation 2 x (8 - 5) do as follows:
- Type 8 and Enter
- Type 5 (followed optionally by Enter) and -
(You can also sum -5 doing: 5, ±, +)
- The lowest position of the stack shows the partial result (3)
- Type 2 and x (or 2, Enter, x)
- The final result (6) is shown on the bottom of the stack