Legal Question in Tax Law in Illinois

Generally not; instead the way to handle it is by an amended return. See a tax preparer for help!

Fraud requires intent. However, evidence of intent is difficult to produce. Fraud then becomes like beauty, it's in the eye of the beholder. If you're concerned enough to seek advice on how to handle the error, the error probably resulted in a material difference in the amount of tax reported vs. the amount of tax appropriate to be reported, Consulting with a tax professional sounds like a good idea. Generally, if an error on a tax return is purely mathmetical, IRS will catch it. If the math error occurred in a computation before the result was reported on a tax return, the return should be amended. The time within which to amend a tax return is generally three years from the later of the due date for the return or the date the return was filed.