Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
Keyboard – most of the space is taken up by the output, with no on-screen buttons. Supports currency and unit conversion.
Notation
The GNOME calculator uses the common infix notation for binary functions, such as the four basic arithmetic operations. Unlike many other calculators, it uses prefix notation, not postfix notation for unary functions. So to calculate e.g. the sine of one, the user must push the keys sin+1+=, not 1+sin, as on many other calculators.
The decimal separator on the number pad is based on the general keyboard layout since version 3.12.3.