Well, one concept that i find very important is this:
If you have 100 bucks and you lose 10% you have 90 bucks. If you add 10% to 90 bucks you have 99 bucks, not 100.
If you lose 50% of 100 bucks it's 50 bucks, if you add 50% to 50 bucks, it's 75 bucks, so to break even on a 50% loss you have to make 100%.
Don't lose. Which is what that article is about, or if you're losing lose less or nothing.