This is an RPN, or stack-based, calculator. You put numbers on the stack, and then you do things to them.
For example, to work out 1 + 3, you'd:
- Type 1
- Press Enter
- Type 3
- Press Enter
- Press +
It's a different way of doing things to a normal calculator, but it can be much more efficient for complicated calculations.
This calculator not only displays the results of calculations, but shows you what went into producing them.
The display shows the current stack. Input numbers are shown in blue, and operations are shown in yellow.
Type a number and press Enter to push it onto the stack.
You can tap any item on the stack to select it, or use the arrow keys to move the selection.
When you push a number, it's inserted below the selected item.
Input numbers inside an operation can't be deleted, but they can be changed, moved or copied.
To change a number inside an operation, select it, type the new value, and press Enter.
When you copy a number, it's given a label to identify it. If you change the value of the number, it changes in all the copies too.
Nested operations are folded up by default. Click on an operation to unfold it and see what's inside.
Click on the result value of an operation, or press the ? key to see more digits.
Keyboard commands
If you have a keyboard, you can type numbers and operations. There are also keys for most of the other on-screen buttons.
Manipulating the stack
| Key | Command | |
|---|---|---|
| ` | Sign | Change the sign of the number being entered. |
| Tab | Shift | Switch to the next screen of buttons. |
| Delete | Drop | Remove the selected item from the stack. |
| w | Swap | The selected item and the one above it exchange places. |
| d | Copy | Add a copy of the selected item to the bottom of the stack. Copies of the same number are linked - if you change the value for one, it changes in all the copies too. |
| u | Undo | When you've selected an operation, undo it and leave its arguments in place on the stack. |
| ? | Show more digits | When you've selected an operation, expand the result to show more digits. More digits are shown as you scroll down. |
Arithmetic operations
| Key | Command | |
|---|---|---|
| + | x + y | |
| - | x - y | |
| * | x × y | |
| / | x ÷ y | |
| s | sin(x) | |
| c | cos(x) | |
| t | tan(x) | |
| S | sin⁻¹(x) | |
| C | cos⁻¹(x) | |
| T | tan⁻¹(x) | |
| ^ | x² | |
| r | √x | |
| p | xʸ | |
| l | ln(x) | |
| L | log(x) | |
| e | eˣ | |
| E | 10ˣ | |
| ! | x! | |
| m | Mean | The mean of all the items on the stack. |
| % | Mod | The remainder on dividing x by y |
| P | π | Add the constant π to the stack |