Thank you! This led me to the right solution, but with this difference:
Searching forms for "IRA SS Wks" doesn't yield a result, and this form didn't appear independently anywhere (at least so far) in Turbotax Home & Business 2020.
The button on IRA Contribution worksheet, Line 13 "Worksheet for social security recipients" opens the calculation, and then shows the form at the very bottom of the "Forms in My Return" list. Until I clicked that button, I couldn't find this worksheet and it's calculation.
Thanks again.
