opm form 1099r box 2a shows amount as unknown,how do i calculate the taxable amount?

[MarilynG1]

After you enter the info from your 1099-R, TurboTax asks follow-up questions to determine the taxable amount (it's usually the amount in Box 1).

If no after-tax contributions were made to the pension plan before distribution (Box 5), the entire amount is generally included in taxable income.

Here's more info on Is My Pension Distribution Taxable?

@JACKSONACTIONJ9