This is a calculator with a virtual tape where you can write values, correction, and change your formula and the resulting value on the same line. You can make a correction by changing the value on the tape.

The calculator has a percent calculation to add or subtract percent values.

Percentage calculations: You can add and subtract percentage values by using the "Add %" and "Subtract %" buttons. The calculator has tax buttons (TX+, TX-) to add or subtract tax.

Tax calculation: You can add and subtract tax values by using the "TX+" and "TX-" buttons. 

Rounding:

The calculator supports three rounding modes: up, down, or 5/4.