Getting started

1.1What this calculator is for#

12345678910

1. Display: shows X, the number you work on (with Y, Z and T above it)
2. f: gold prefix for the functions printed above the keys
3. g: blue prefix for the functions printed below the keys
4. ENTER: separates two numbers
5. Back arrow: delete a digit, or clear X
6. CHS: change the sign
7. STO: store X in a register
8. RCL: recall a register
9. R/S: run or stop a program (g R/S switches program mode)
10. Σ+: add a statistics data point

RPN Scientific 15 is built for people who like to see every step of a calculation. You never type a long expression and wait for the answer. You work on one number at a time, and the in-between answers stay in view on a small pile called the stack.

It has scientific functions, hyperbolics, polar and rectangular conversions, statistics, linear regression, a root finder (SOLVE), numeric integration (∫xy) and keystroke programming. Programs can use labels, subroutines, flags, loops and indirect addressing.

See also How RPN and the stack workHow the RPN stack works

1.2The display and its indicators#

The display shows the number in the X register: up to ten digits, with a minus sign in front of negative numbers. Large numbers are grouped with commas, for example 1,234.5000. The app also shows the other three stack levels (Y, Z and T) above X.

While you type a number, the display shows exactly what you have typed so far. After you press any operation key, it shows the result in the current display format (FIX 4 when the calculator is new).

1.3The f and g shift keys#

Most keys do three jobs. The main job is printed on the key. A second job is printed in gold above the key: press f first, then the key. A third job is printed in blue below the key: press g first, then the key.

Press the prefix, release it, then press the function key. You press one key at a time. For example gx²√x is x² (the square), and fFIX7 starts the FIX display setting. If you press f or g by mistake, press the other prefix, or any key that has no shifted function, to cancel.

1.4Your first calculation#

To add 3 and 4, key in 3, press ENTER to tell the calculator the number is finished, key in 4, then press +. The answer appears at once. There is no equals key.

Example 1.1

Add 3 and 4

1. Key in 3, press ENTER, key in 4 and press +.

   3ENTER4+

ENTER is only needed between two numbers typed one after the other. After an answer you can simply type the next number.

1.5Clear a mistake and correct a number#

While you are typing a number, ← deletes the last digit. Once the number is finished (after an operation or ENTER), ← clears X to zero. gCLx← (CLx) always clears X.

Example 1.2

Delete a wrong digit while typing

1. Type 1 and 2, press the back arrow to delete the 2, then type 5. Press ENTER, key in 3 and add.

   12←5ENTER3+

Example 1.3

Clear X with CLx and carry on

1. Key in 5 and ENTER, key in 7, then clear it with g CLx. Key in 2 and press +.

   5ENTER7gCLx←2+

1.6Type with a laptop keyboard#

On a computer or Chromebook you can type instead of tapping. The digits, the point, + − * / and Enter work as you would expect, Backspace is the back arrow, and ^ is yˣ. Letters give common functions.

See also Type with your computer keyboard