Mathematically I would approach this in the following steps:If you took Bryan L.'

I am a math guy....does anyone happen to know the mathematical formula for calculating this?

So it's overstated by a factor of nearly 4, which tallies with my commonsense that water supply only (not heating; that's individual) for a 1/2BR unit shouldn't be $57 per month.So given this piece of mathematics, I'm pretty confident I can get the expenses lower than stated.

The 2% Rule is the same thing as using the 50% Rule and applying a 12% Cap Rate on the annual NOI.I was looking at some properties and noticed I got the same value using the 2% rule and using the 50% for an estimate of NOI and happened to be using a 12% Cap.Being a math dork I did write it out symbolically and they both reduce to the same mathematical equation (Which BTW is just multiply the monthly rent by 50).

You can if you like the house, mathematically it might not be the best option but not all decisions have to be math based. 

In the world of mathematics, you can NOT use a number unless it is accurate. 

This looks like an excel function, but what is the actual mathematical equation?

Oh okay, now the lender has some security just in case you can't pay back the loan...Lets say you are purchasing a property for $100k and for sake of argument and mathematically simplicity the down payment is zero. 

Familiarize yourself with all the mathematical ways to approach prospective deals.  

I have previous experience in the marketing field, but most recently have been teaching various mathematics courses at a local high school.