Another way of looking at it mathematically is that it will cost you 800/month, one month for the rehab and one month at a minimum to fill.

For example, you might want to seriously consider doing some direct marketing to owners of small multi's in your city, especially those that look like they might be poorly managed, or have an absentee owner.It's going to be challenging getting ahead when paying 100x mthly rents for small multi's at this rent point, that's just a mathematical reality.

These are of course overly simplistic mathematical assumptions, and real life results will obviously vary. 

I love mathematics very much.

If you look at it mathematically which people on this forum would agree with, then why I pay the bank $10,000 in interest to get back $2500 in a refund saying you are in the 25% tax bracket?

Mathematically it can't go down every year or else we will reach 0.

It's part psychological, but also part mathematical in nature.

Although being highly leveraged can mathematically work out well, being too highly leveraged is a huge risk.

@Todd HajecThe simple mathematical answer is pay off the high interest credit card debt first.  

The likelihood that you could buy out the investors from refinance proceeds alone isn’t likely to work mathematically unless you inject a lot of your own capital.