The sportsbook is out to win your money.  Never doubt this.  They will offer you all manner of ridiculously bad bets dressed up as something that appears to be a good deal.  They do this to increase their profits from the bettors who don't understand the math.

If You Hate Math, Don't Try to Make Money Betting on Sports.

Sportsbooks will also offer some bets where you can get a small edge, an advantage.  If you're serious about finding those bets where the book is vulnerable then you'll need to understand math to exploit that vulnerability.  The basics you'll need are:

A basic comprehension of statistics, particularly inferential statistics.  Inferential statistics are used to make predictions about a population based on a sample.  This is the key to getting an edge on the books.  Here is an example, made up out of thin air (it has no basis in any fact or data).  Say you have looked over some MLB data from 2002-2007 and have found that when the home team starts a right-handed pitcher the day after a rain delay, that home team wins 63.6% of the time.  From this you derive the hypothesis that looking for situations where the home team starts a right-handed pitcher the day after a rain delay could be profitable.  In order to validate your hypothesis you will need to do some statistical analysis.

You will also want to use statistics to evaluate your own results.  You should keep accurate records of your bets so that you can periodically review your results over time.  Rest assured that no edge over a sportsbook lasts forever.  If your right-handed pitcher scenario from above proved to be one where you did get an advantage on the book, they will some day figure it out and that edge will be gone.  You may not realize this if you are not continuously monitoring your results.

And you may want to use math, notably the Kelly Criterion, to determine your bet sizes.  Once you find an edge on the books you'll want to take maximum advantage of that edge in order to maximize your bankroll growth.  If you do not understand how to exploit your advantage, it is possible to overbet in such a way that you are likely to lose money in the long run - even with an advantage situation!

I will take some time to explain many of the basic math concepts needed by sports bettors.  Fortunately, you can use spreadsheets and calculators to do most of the heavy lift for you.  I will also demonstrate how to use those spreadsheets and calculators using MS EXCEL.  You may choose to use a different calculator.  Understanding the underlying concepts is important, however, as you will be exploring unique situations with your data.  If you know the concepts you can successfully investigate and conclude your own hypotheses.

I will also provide some useful reference suggestions along the way for those who want to reinforce or expand their knowledge of sports betting math.