As a mathematically minded person, that's what I look for.

Only if you are bad at mathematics, have wife who spends to much of your budget and ONLY if he is financial planner specialized in real estate...a guy who is an experienced RE investor!

As it has been mentioned, there are many, many mathematical calculations to utilize, but not one of them, on their own, are determining factors of a decision to purhcase or not to purchase.

Hi All,    I'm scrolling through properties just so I can get my mathematical up and discovered this property where I was running comps for.

I would take a property and calculate mathematical using the THE 50% rule and the 2% rule and making a estimate what the cash flow would be .

Maybe I'm just terrible at mathematics, but I'm struggling to figure out how to calculate ROI from a house purchased via my HELOC.The numbers I'm giving below are just examples.Let's say that I find a rental property which costs $50,000.

Don't think because they are "big" guys that they are right.I started this way as well and I learned early on that most people here have no clue what they are talking about.So back to our mathematical prove and disprove theories lesson...So take my case...and to add..

It may not be sexy but the best mathematical decision may be to pay off the high interest debt. 

@William WironenOnce you cash out from the refinance, you’ll have 0 cash left in the deal, so mathematically your return is infinite!

Foreclosing ASAP is a way to get in front of that mathematical "certainty" and cut my losses.By contrast if 4% is a normal interest rate and 8% is "normal" annual appreciation, equity (ie, the safety of my position) is actually still going up each year.