Changes:
-Added unlockable items: one background and 5 buttons. Unlocking conditions can be found in the "Collection" section.
-Added a "Collection" section where you can view all the buttons you have and read about their actions.
-Added 6 new buttons:
-"Subtract from 100": subtracts the current number from 100 (if the number is greater than 100, the result is 0).
-"Morpher A": replaces the penultimate digit of the number with the selected one.
-"Morpher B": replaces the last digit of the number with the chosen one.
-"Equalizer": sets all digits of the current number to the chosen digit.
-"Mining": adds 1 coin when used (receives 1 charge each round).
-"Exchange": adds one to the current number, spending one coin (if more than 0).
Changed the actions of the following buttons:
-"Battery": adds 1 charge to a random button (receives 1 charge each round).
-Added separate sound and music controls in the settings. Also added a background change feature.
-Fixed a bug where some sounds did not depend on settings.
-Added difficulty level 5: After defeating the boss, charges on some buttons change.
-Added difficulty level 6: Maximum number of buttons in the calculator: 24.
-The game now shows notifications for which button has been discharged or charged.
-Fixed a bug with the "Near" button.
-Fixed several critical bugs.
-The button descriptions on English have been changed.
-New boss: "You must use button X; otherwise, the answer will not be counted."
-New boss: "You lose 1 coin when using the button (if more than 0)."