Hi (Total Deductions)

Hi everyone,

My first language is Italian. I am studying Business Administration.
I discovered this website while I was looking for an answer about calculate "Total Deductions" in Excel.
I have calculated Gross Pay, Superannuation (9%), Tax (21%) and Net Pay, but I don't well the meaning and how to calculate Total Deduction.
At first, I did Tax - Superannuation, but I am not really sure. May someone helps me?
I have attached the file.
Thank you very much.