You can type an expression into the text field at the top of the calculator or press the buttons to generate an expression string.

All the text field hotkeys are enabled when editing the expression string. You can therefore navigate the string normally. When using the function buttons to insert function tokens into the expression text field, the cursor position is updated to the following local position in the string. This lets you simply tap with a pen and insert expression tokens without having to move the cursor position manually.

Expression functions and operators are grouped by categories. The Math category of functions is available by default. Although you can type into the text field directly, showing the buttons helps you to memorize the available functions.

Clicking the C button clears the expression string.

Once an expression is used to drive an attribute value, you can no longer keyframe the value. You must delete the expression before setting a keyframe.