I am assuming that there is a tax schedule somewhere that indicates the taxable amount but I am unable to find it.
To see the Social Security Benefits Calculation Worksheet in Turbo Tax Online version you would have to save your return with all the worksheets to your computer. Or if you are using the Desktop CD/Download Software you can switch to Forms Mode (click Forms in the upper right) and click on SS in the list on the right side.
But....If you go to Tax Tools in the left-side menu, you can get a preview of your form 1040.
That income, and the amount taxable should show up on lines 6a & 6b of the form 1040 (or 1040SR). Line 6b is the taxable amount of line 6a.....but if you've also entered SSA-1099 forms too, for you or your spouse...those will be added into line 6a & 6b
If you see those $$ you just entered, on lines 4a,4b or 5a,5b, then you entered your RRB-1099 form in the wrong area.
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Remember a form RRB-1099 is what goes in at the Social Security menu line
An RRB-1099-R goes in along with the other 1099-R forms