Don't panic when that letter from the Internal Revenue Service arrives. Many tax notices can be dealt with simply and painlessly.

Each year, the IRS sends out millions of notices. Most of these let taxpayers know of common filing mistakes that mean a change in a tax bill. Others request additional information about a return. The notice normally covers a specific issue and offers equally specific instructions on what the IRS wants from you to settle the matter.

Commonly issued tax notices
Each IRS notice is identified by its CP, or collection process, number found in the upper right corner of the first page of the correspondence. Each also has a title in large, bold print near the center of page one.

Here are the most common tax notices and why they are issued:

Common tax notices

CP number Tax reason CP 12 Math error -- Overpayment of $1 or more CP 14 Balance due, no math error CP 49 Overpaid tax applied to other taxes you owe CP-90 & CP-297 (sent simultaneously) Final notice -- Notice of intent to levy and Notice of your right to a hearing CP-91 & CP-298 (sent simultaneously) Final notice before levy on Social Security benefits CP 161 No math error, balance due CP 501 Reminder notice -- balance due CP 504 Urgent notice -- balance due CP 523 Notice of default on installment agreement CP 2000 Notice of proposed adjustment for underpayment or overpayment

If your notice isn't listed above, you can call the IRS at the number listed on your notice or at the agency's toll-free help line at (800) 829-1040. Hearing-impaired and TTY users can call (800) 829-4059.

First, check your information
The first thing to do when you get a tax letter is to pull out the tax return in question. Compare your file copy with the IRS notice. You might find that you did indeed add when you meant to subtract or transposed a number or put an entry on the wrong line.