Question regarding tax amount

I was reviewing my 2016 return (prep for 2017).  Filing jointly.  Line 43 income is $73,159.  TT computed a tax of $1,143.  However, when I look at the tax tables, I find that tax should have been higher.  How do I check that my tax computation is correct?  How do I find out where TT came up with that tax amount?    Thanks