Can any experience investors give some insight into the most important mathematical formulas need to evaluate a deal for profitability?

It's a mathematical problem, with dollar $ign$ in front of the numbers (not percentages).

Both mathematically and reasonably this method puts the burden and reward in the proper places.   

It made the most sense mathematically and I loved the control it provided.Fast forward 2 years.

It seems mathematically impossible to cash flow with a loan if the cap rate is below 7%.

I assumed having a pool at a rental would be a bad idea but this actually puts it into mathematical details.

So, in general, you think the tax code is political and not unbiased mathematical formulas?

Waddles wrote that getting rich was an  exact science and that if you do the things he says, it is as certain as a mathematical equation that you will become rich regardless of age, sex, race, background, etc.

It doesn't have to always be the optimal mathematical return.

You can but mathematically the return will be less but there can be psychological benefits to all cash