How do they calculate the federal adjustments? I don't know where to find these values.

@igomes08 

We don't know what you're working on specifically that prompted your question since no information was provided.  So most commonly I would think you are asking about the Federal adjustments on the 2021 Form 1040.  If it's something else, you need to explain more.   Or are you working on a state return and getting asked something about Federal adjustments?  If so, you'd need to name the state so someone familiar with your state can comment.

I'll go ahead and talk about Federal adjustments that can appear on the 2021 Form 1040.  Some people may not have any adjustments while others may have several.

Are you referring to Federal adjustments shown on a 2021 Form 1040, Line 10?    If so, those come from Schedule 1, Part II.    There are quite a few possible adjustments.   Below is a link to an IRS image of the Schedule 1, and you'll see a lot of possible adjustments in Part II (page 2 of the form.)    They are totaled there on Schedule 1, Part II, then the total flows to the Form 1040, Line 10.   They come from a number of places in the TurboTax interview.    If will vary from filer to filer.  There may be none, or there may be several adjustments.

2021 Schedule 1 (for Form 1040)

https://www.irs.gov/pub/irs-pdf/f1040s1.pdf 

If your return is still in preparation, you can preview your Schedule 1 during preparation and prior to paying.  Here's how:

• With your return open, go to the left column menu and click on TAX TOOLS, then TOOLS.
• In the Tools popup window, choose View Tax  Summary.
• Once that summary displays, go to the left menu column again and choose Preview Form 1040.
• That will bring up the Form 1040 (or Form 1040SR) Worksheet as well as Schedules 1-3.