Link: Determining Simple Probability. If you are wanting to practice for the upcoming test, please use this web site. It will help you work problems to calculate the decimal number associated with something happening.
You may use a calculator because the numbers are big enough that it would be difficult to do this with pencil/paper. Be sure to enter an answer of .33 as 0.33 or an answer of .78 as 0.78.
If you forget these directions, there are some on the page itself if you scroll down. There are also 3 variations of the basic practice style that you can find near the bottom of the webpage.
Have fun and build your confidence before the test.