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U.S. Department of the Treasury Internal Revenue Service 1040 Individual Income Tax forms for the 2015 tax year. Michael Nagle/Bloomberg via Getty Images hide caption
toggle caption Michael Nagle/Bloomberg via Getty Images
A lot of the stuff on IRS form 1040 — the basic tax form — is straightforward enough. But there are a few lines that you look at and say: What is that? And how did it get on my tax form?
