Uses Math.js for evaluating expressions. If it works there, it should work here!
How to use
Select an expression in your document. For example, ((((5*5)+1)/2)-10)^2
Enter the Command Pallette (F1), and type "calculate"
The evaluated result will appear after your selection
Counter
The $i in any selection is replaced by the index of the selection. For example if you have three identical selections 2*$i+1 the results will be 3, 5 and 7.
Available Commands
Calculate calculates selected expression, and appends "=" with the result
Calculate and Replace calculates selected expression, and replaces it with the result