Comment 1 for bug 1756407

The entering of amount is not that much complex you describe:
- if you use tab from the date, the amount is selected and typing 80 + enter seize what you want with 3 key typing.
- ctrl+a into the amount select all and enable doing the same
- the amount enable to enter . and , as well
- the amount is plugged to a spin, I should probably remove (but some people use it to adjust some cents)

I really don't see what should be more easy that typing numbers into the keyboard or num pad, like you will do for memo or other text fields.

Last, if a calculator is required, you can use an external one, adding one, is not just plug an applet, it requires coding with all the complexity of what a calculator must do.

I keep this wish open for now, we will see if some others second you on this.