Using probability tree diagrams to teach probability is helpful - but sometimes kids (and grownups) need a little help with them.
This "cheat sheet" has 5 pages of detailed (and easy to understand) explanations on how to calculate the various probabilities - including conditional probabilities.
Once students understand how probability trees work, they can effectively use them as tools.
Make sure you also download my Probability Trees Puzzles free worksheet, too!
And for more information, see http://mathfour.com/finite-math/probability-tree-diagrams-as-puzzles.