It's not trigonometry or algebra, just simple 5th grade math. 

Original cost = Sales price / markup.see the 3rd examplehttp://www.purplemath.com/modules/percntof2.htmIf this is giving you trouble you might want to brush up on some basic algebra, especially if you haven't practiced it in many years.

Math you can break down into multiple parts.For real estate if you have a grasp of addition, subtraction, multiplying, division etc. then a lot of calculations should be able to be made.If by saying you are not good in math you mean calculus, trigonometry, and algebra etc. that stuff is more used in other occupations like a scientist etc.

Calculus or trigonometry may seem irrelevant, but it really develops your algebra skills - which are very important in investment analysis. 

Of that remaining 10%, most of them have a "not technically sales" sales job... a high school teacher is "selling" those kids on studying and doing their homework on a daily basis, for example, and on the notion that Algebra isn't mysterious witchcraft, in fact it's something that you can understand and apply to your daily life.

How to:1 - ...find Money2 - ...analyze Markets3 - ...use (not spend) Money4 - ...make a REI Plan...and stick to it5 - ...take emotions and flush them down the porcelain bus6 - ...control Risk by learning what Risk is, and how it applies to REI7 - ...learn the difference between cost to you and cost of the deal8 - ...separate yourself from the mindset of a homeowner and a REI9 - ...separate yourself from the analysis of Stocks/Bonds and RE10 - ...and, How to Do Algebra...in all its glory.

If you're looking for freedom, perhaps a better goal is to accumulate enough assets to replace your earning power.Why our school systems teach algebra but not this simple concept, is beyond me.

So we will have to see what happens.Top it all off the owner's son sits right next to mine in Algebra at high school and have become good friends...and regularly walk to school and home together.

I believe they are the two Bibles of REI, and over the years have come to the opinion that too many REI don't use what these books offer, or don't really understand how important they are to their success.See below---------,                          |                          |                          |                          |                          V         Geometry and Algebra.

Knowing how to do simple algebra, calculate the return on investment, create spread sheets, etc. is critical.