I use a simple formula of 4 figures:1) What will the home sell for after it's fixed up (ARV).

But using a really conservative income formula you will be able to determine if going the STR route is worth it vs. any other investment strategy. 

Of course, there wasn't anything he could do about it other than to say "whelp, that's what our formulas show". 

Good Pod castLance Edwards - Small Apartment Buildings- https://www.apartmentwealthinfo.com/Brad Sumrok - https://www.bradsumrok.com/Ron Legrand - http://www.ronlegrand.comPodcasts:The Commercial Real Estate Show with Michael BullTarget Market Insights with John CasmonBest Ever Real Estate investing Advice with Joe FairlessThe Real Estate Guys Radio ShowThe Wealth Formula Podcast with Buck JoffreyWheelbarrow Profits with Jake and GinoGood Luck

A class will teach you basic skills of how to use excel, how to create and input formulas that can carry over throughout cells and sheets, how to create pivot tables and sensitivity analyses, so you don't have to manually redo your work time and time again.  

Is there a simple formula you would use to determine your monthly payment and property insurance?

The sheets are filled with formulas that make it easy.

No formulas. 

What that means is that the county has some very complicated formulas that split up and assign a portion of the $15 million to each property. 

That being said, consider working outside of a formula.