Fitbit SimpleCalculator Operations

(last update 2024-01-10  Versions x.2.11- Versa's, Versa 2,3,4 , Sense, Sense 2)     

Professional Calculator


Main screen

Virtual buttons

Quick Guide Overview

For quick access, a great simple Classic calculator, inspired by the beautiful HP-41 calculator

Has tactile feedback to ensure reliable calculations

Includes an optional transparent ticker tape to show recent calculations

Includes 4 virtual buttons shown in the display at start up

Adjustable decimal places.

Whole [integer] results don't show any decimal point or places

Current operator and number of decimal places are shown on the right of the display.

Tactile feedback On or Off is shown on the left of the display.

Can do constant calculations, including percentages, for tips

Can also work in Reverse Polish Notation mode like the original HP-41

Virtual buttons

1) Clr -Above the minus key

Tap once, clears the current calculation,
Tap again to see About information and Close the App.
Double tap to do quick close. [The back button will also Close the App]
The App will auto close after a time of no activity.

2) Shft - Shift key, above the 7 key

Tap to enter Shift mode [works with buttons with gold writing above]
Tap a second consecutive time to switch back and forth between Classic and RPN calculation mode
   (New: Calculation mode is retained between use)

3) Del - Above the 8 key

like Backspace, deletes last entered digit

4) List -Above the 9 key

Tapping shows/hides the popup ticker tape list, for verifying calculations

Shft before List to get a transparent pop up of the calculation registers

Special features:

1) Negative number input:
Tap the 5 button and swipe Up to toggle the displayed number negative or positive.

2) Tactile feedback:
Tap the 5 button and swipe Left to disable or Right to enable. A bell indicator on the left of the display shows state

3) Last operation recall:
The last operator and operand are remembered and can be applied to any displayed number by pressing on =, entering a new calculation clears this function.

3 + 6 = result 9
5 = result 11
2 = result 8

4) Counter mode:
Enter + 1 = [result 1], each subsequent tap on = will increment the display by 1

5) Shift mode, Decimal places:
Tap the virtual Shift key [above 7] followed by 1 and then a digit 0 to 9 for the number of places required.

EG. Switch from 2 to 4 decimal places
current display 1.67
Shift  1 4,  result 1.6700 [number previously rounded]

Shift mode, Pi:
Tap the virtual Shift key [above 7] followed by 0 and Pi will be entered in the display

7) Percentages:
To add 12% tip - to 25.10

Shft 2 [%]
result = 28.11

Tap Shft 2 consecutive times to switch back and forth between Classic and RPN calculation mode.
[In RPN mode, Enter is shown instead of =]

Reverse Polish Notation feature


Shift mode keys,

Extra Shift keys available: Register down rotation and X <> Y register exchange

2) Registers
The registers X, Y, Z, T, behave as for an HP calculator

To add 12% tip - to 25.10

Shft 2 [%]
result = 28.11

Other features

    1) Tap List to get a transparent pop up of the calculations ticker tape

    Ticker tape calculation list

    ticker tape

    • The list is transparent and calculations can still be performed with it showing.
    • To clear the list, tap the virtual CLR button with it showing.
    • To remove it from view tap the List button.
    2) Tap Shft before List, to get a transparent pop up of the calculation registers

     Ticker tape registers list

    ticker tape

    • The list is also transparent and calculations can still be performed with it showing.
    • To remove it from view tap the virtual List button.

    Closing the App

    • To do an immediate close of the Calculator, press the watch back button.
    • To see the About and then close, double tap on the virtual CLR button
    • or after a couple of minutes it will auto close
    • Quick double tap of CLR will also do a quick close

    Watch integration

    • SimpleCalculator must be installed separately on the watch to be used as an Addon for SimpleClockPro see:
    •  Once installed, SimpleCalculator can be started by clicking on Active Zone minutes
    • When SimpleCalculator is ended the clock face shows again
    • SimpleCalculator can also be installed as a standalone App, in this case,
    • Tip: For Sense and Versa 3 watches, Use the watch Settings to assign SimpleCalculator
    •  to the watch long press short-cut
    • For All watches SimpleCalculator can also be moved to the first Apps watch screen

    : Transparency

    • App uses full Brightness for helping with better contrast for it's transparent options.
    • This is automatically disabled between the hours of 20:00 and 07:00
    • If necessary, in the watch Settings menu temporarily set Brightness to Max before starting.

    HP-41C and Reverse Polish Notation aficionado's references:

    1) Android HP41C calculator

    2) HP41C manual

    Covers aspects of using the Reverse Polish Notation and register usage.

    3) Original HP-41C  [1979]     

    The first programmable calculator, HP-65 [1972], was used in space. It had a magnetic card reader incorporated for storing and reading programs or data into memory.

    Later the upgraded HP-67 [1976] was produced then the switch from red led display to LCD in the form of the HP-41C saw production in 1979, which also had connectable card reader, printer and memory modules.

    Image of
    Original HP-41C



    Calculator releases (V4 - Ionic & Versa's, V5 - Sense, Versa 3, V6 - Sense 2, Versa 4)

    Vx.2.11 - 2024-01-10

    • Tactile feedback improved - 5 button feedback cannot be turned off

    Vx.2.10 - 2022-07-19

    • Darken screen at night [20:00 - 07:00]
    • Retain Calculation mode [and keyboard layout state] for next time

    Vx.2.09 - 2021-09-13

    • Improved calculation precision and calculation process

    Vx.2.08 - 2021-08-10

    • Improved tactile feedback for all operations and touch sensitivity
    • Added 30 second stay on to stop display blanking during calculations
    • Add shift indicator
    • Added Reverse Polish Notation (RPN) calculation
    • Improved keyboard layout for grater clarity
    • Added display of RPN registers as a transparent display
    • Added % operation
    • Improved calculation precision and rounding

    Vx.1.16 - 2021-06-13

    • Improved negative number processing
    • Improved ticker tape presentation

    Vx.1.15 - 2021-06-06

    • Initial release