With those buttons you can select the number system (radix) you want to use – Decimal, Complex, Hexadecimal, Octal, Binary.
Here you can select how the decimal and complex numbers are displayed (with or without an exponent), and also the trigonometric mode (degree or radian measure). For the binary modes (hex/oct/bin), the buttons will instead present a word size selection.
This group gives you mouse access to the decimal setting (i.e., how many decimals to display), and also the three pushbuttons Configure, Help and Exit.
XCALC buttons
On the XCALC main window there are plenty of buttons that can be clicked, arranged in groups that can individually be switched on or off (see
configuration):