Probability distribution--should these equal one?

Hi there,

I'm supposed to prepare a probability distribution for the following question:

Two balls are drawn from a bag in which there are 4 white balls and 2 black balls. The number of black balls is being counted.

Okay.

So x = number of black balls.

Doing combinations:

http://img.skitch.com/20101004-g1pjm...f12grqeic6.jpg

Should those equal 1, or is it okay that they don't? I got .088 + .263 + .329, which doesnt = 1. Are my calculations correct?

Thanks!!