HeatherPLO
Intuit Alumni

After you file

Please see the answer above from Critter:  

 

9021– Reference Code for all math error conditions.

Note that a "math error" can occur if you make a data entry mistake, or forget to claim some income, and thus the refund amount is incorrectly calculated.  The IRS will be sending you a letter. They do not notify TT. 

 

Source

**Say "Thanks" by clicking the thumb icon in a post
**Mark the post that answers your question by clicking on "Mark as Best Answer"