Where can I adjust a charitable contribution? On my 1040/1040SR, I have a charitable deduction where lines 10a and 10b do not add up for line 10c.

TurboTax ONLINE

Click Tax Tools on the left side bar

Click Tools from the drop-down

Click the "Topic Search" box on the screen

Type or scroll down to    standard deduction and exemptions

Click GO 

The next screen gives you an option to change your selection from Standard to Itemized and back. You do not need to change your selection

Scroll down to the bottom of that screen and click CONTINUE

The next screen is the Charitable Cash Contributions under Cares Act screen

IF YOU ARE CLAIMING STANDARD DEDUCTION enter the amount of cash contributions you made, up to  300

IF YOU ARE ITEMIZING DEDUCTIONS enter 0

Scroll down and click Continue

Click Continue on the next screen

To verify, click “Review” if necessary, in order to get Tax Tools on the left side bar

Click Tax Tools on the left side bar

Click Tools on the drop down list

Click “View Tax Summary” on the “Tools Center” screen

When the next screen appears (Review Tax Summary) ON THE LEFT SIDE BAR you should see “Preview my 1040”

Click “Preview my 1040” on the left side bar

Scroll down to line 10b on the 1040.

DESKTOP

Go to Step-By-Step input

Click Federal

Click Deductions & Credits along the top

Click “I’ll choose what I work on”

Edit or Update Donations to Charity in 2020 if needed, then click “Done with Charitable Donations”

Scroll down the “Your 2020 Deductions & Credits” screen and click “Done with Deductions”

Click Continue on the “Let’s Check Your Deductions and Credits” screen

Continue through the following interview questions until you get to the “Here Are Your 2020 Deductions & Credits” screen

Click Continue

If the next screen says “The Standard deduction is Right for You!” click Continue

ON THE NEXT SCREEN enter the cash contribution made in 2020 and click Continue

Your 1040 should update

“The new "up to $300 above the line cash charity donation" is available for tax year 2020. This allows a Taxpayer to claim up to a $300 credit which is subtracted from income on the 1040 line 10c if the Taxpayer is claiming the Standard Deduction. (If you Itemize Deductions, all your donations will be listed on Schedule A.) “