Did you ever look at the bill at a restaurant and struggle with the math because you wanted to leave a little more than usual for some good service? I bet you didn't use Justin Timberlake math.

Justin and some friends were at The Crystal Cologne Club in Cologne, Germany and were partying through the night and apparently the drinks were on the house, according to yahoo.com. Justin was so appreciative he decided to leave a tip. But not just any tip.

Justin decided to give a big thank you. How big? Try nearly $4000. Now I know that kind of money is no big deal to a guy like him. But it's not a big deal to a lot of other celebrities who don't leave a $4000 tip, so good for Justin. And really good for the workers at The Crystal Cologne Club.

I'm no math whiz, but if the bill is zero and the tip is $4000, that's more than 20% right?