Backspace to delete last number.

End to make number negative. Input the number and than make it negative. For example: 12 * 3 (press -N) >> 12 * -3 = - 36

Operators as they are.

Esc or Delete to delete all numbers.

POW is used to power number. For example: 2 POW 3 = 8

Control √x

Unfortunately F-keys are inaccessible to prevent their defaults.