Retirement tax questions

I apologize for the error and incompleteness of my question.

 

  • The amount stated in "... It is not clear to me what portion of the $100,00 amount in Box 1 is attributable to earnings..." should be $100,000, not $100,00.
  • My final question was not complete. Basically, if I create a second 1099-R form, how will I know (how can I found out) how much of the $100,000 is attributable to earnings on the after-tax contributions.