On Form 1040 lines 8 -11 I keep getting on error on #10 Adjustments to income. Chartible contributions is not between prescribed upper and lover linits. No matter what?

I was able to enter the $300 charitable contribution in TurboTax Online Deluxe by following these steps:

• Down the left side of the page, click on Federal.
• Across the top of the screen, click on Deductions & Credits.
• Scroll to the bottom of the screen and click on Wrap up tax breaks.
• Continue until you receive the screen Based on what you told us, the Standard Deduction is best for you.  Click Continue.
• You reach the screen Charitable Cash Contributions under CARES Act.

• Enter your charitable cash contribution.  If you enter more than $300 (Single taxpayer), your deduction will be capped at $300..
• Click Continue until you reach the end of Deductions & Credits.
• Across the top of the screen, click Review, then Continue.
• After Review is complete, click Tax Tools in the lower left hand corner of the screen.
• Click Tools.
• Click View Tax Summary.
• Click Preview my 1040 in the left hand column to review the entry on line 10b of the 1040.

This TurboTax Help states: 

• For 2020, even if you don’t itemize, you may take a charitable deduction of up to $300 for cash contributions made in 2020 to qualified organizations.