Hi loay elhaj,

To Get the sum of cells in excel report you can use the following.

worksheet.write_formula('A1', '=10*B1 + C1')

This will print the result of formula in A1 column.

For more info related formulas you can refer below link

https://xlsxwriter.readthedocs.io/working_with_formulas.html

Hope it will help you.

Thanks & Regards,
Email: odoo@aktivsoftware.com
Skype: kalpeshmaheshwari