Calculator
If you need to calculate (or check) something, you can use the built-in system Calculator.
Just click on the Help button in theDocuments / Add document to openCalculator.
You will find a engineering calculator. If you want to switch it to simple, click on ? in the upper left corner and then >, located below it. And from the third, you can change the decimal point (dot or comma).
To close the calculator, click somewhere outside.