My turbo 1040 line 15 shows taxable income of 83,220 and line 16 (tax) of 9,842. per irs tax table, joint tax for 83,220 is 9,890. why does turbo tax not agree with irs?

You must have some capital gains from sale transactions or capital gain distributions from a 1099-Div.  Capital gains are taxed a the capital gains tax rate, which in your case is probably 15%.  Your tax bracket for ordinary income is 22%.  Check you return for an amount on line 7  If my math is right, it should be around $690.

Any long term capital gains taxed at 0% (or at a lower rate than ordinary income)?

I see where this is going, and I'm sure it will answer my question!  Thank you!

Got it - thanks!