How will I do this calculation for this project, which is salary $120, 000 and tax deduction #17, 600

While we are more than willing to help those that are stuck, that doesn't mean that we are here to do it all for you! We can't do all the work, you are either getting paid for this, or it's part of your grades and it wouldn't be at all fair for us to do it all for you.

So we need you to do the work, and we will help you when you get stuck. That doesn't mean we will give you a step by step solution you can hand in!
Start by explaining where you are at the moment, and what the next step in the process is. Then tell us what you have tried to get that next step working, and what happened when you did.

If you are having problems getting started at all, then this may help: How to Write Code to Solve a Problem, A Beginner's Guide[^]

Quote:

How will I do this calculation for this project ...

'this project' is not a description of the project you working on.
'this calculation', the end of title do not describe any calculation because we have no context.

As a requester, your job is to give a precise description of your problem on the project. Showing your work so far may help us understand what is your problem.

Wilde guess, in case the project is related to IR in your country, remember that most of us are not from your country and IR calculation is unknown from us.