Instruct: Classify a review into positive or negative sentiment.
Query: Try to avoid of mathematics.

First, I read a copy in a library, it might be old. However, the error seems not a typo. Maybe, he is good at investment. Maybe he could teach others how to avoid of mathematics. But if when he is talking in Mathematics, he'd better say it correctly. This guy don't know how to calculate "Expect Value"! If one use his formula to calculate risk, one may believe he is going to win while he is more likely to lose. So, it might be a good book. But better read it with caution.