Which tax form would you file to correct a mistake on last year's federal tax return?

For a tax form, the 1040X is pretty easy to complete. Basically, the IRS wants to know what you originally reported, what your corrected numbers are and why you are making the changes. There's also a section for adding or subtracting personal exemptions in case there was some confusion as to whether you properly counted someone as a dependent.

And, in most cases, you can change your filing status, which could get you a bigger refund. For example, a new divorcee filed this year as a single taxpayer. But that cost her some tax money because she's got custody of the kids. She should have filed as a head of household, which would have provided her with a larger standard deduction