I am not able to resolve the following circular dependency. In order to get Adjusted Gross Income (AGI) one needs to subtract an "IRA Deduction" from Gross Income. Modified AGI must then be computed as a function of AGI, in order to determine the IRA Deduction. What am I missing here?
Note: I am referring to this article: https://www.thebalance.com/how-to-calculate-your-modified-adjusted-gross-income-4047216. Virtually every article one can find online introduces this circular dependency. I realize that I could dig through the official forms, but I was hoping some expert on here could directly point me to what I am misunderstanding.