I apologize for the delay in answering this follow up question. We have been doing some major home renovations and unfortunately, the electrical system got knocked out for a few days. (Somebody missed their mark and cut the electrical service by mistake)
First, I assume you mean the amount is $2821.44
When you receive a 1099R that does not have any entry in the box that says "taxable amount" and a check in the box that says "taxable amount undetermined', the taxable amount depends on whether or not the person ever contributed to their retirement/pension plan while they were working.
If your mother never contributed to her retirement/pension plan, then all of the distribution is taxable.
If your mother did contribute to the plan, then you must spread the % she contributed vs the total $ amount in the plan over her life expectancy per IRS tables. I have supplied the links below that tell you how to do this from Publication 575 (2007), Pension and Annuity Income . However, given the small amount of money you stated your mother received, the truth is, it may not be worth going thru all the calculations. If you consider the whole amount as taxable, and your mother, after taking into account her standard deduction and personal exemption, has no tax liability, then does it really matter that only $2600 of her $2800 distribution (for example) was taxable?
Here are the links though just in case you wanted to calculate this out:
Cost (Investment in the Contract)
How to use the Simplified Method.
Again, I apologize for the delay in answering this. With any luck at all, my electrical problems should be over, and I should remain avalilable should you have any follow up questions.