Changes

[[File:Addition and Subtraction 3 Activity Option Screen.png|300px|thumb|center|Addition and Subtraction 3 Activity Option Screen]]

Press 1 to see a teaching example. You may see as many examples as you want before doing the practice exercises. Press 2 to go directly to the practice exercises. Follow the directions on the screen for each activity. As you do the exercises, the computer keeps track of how you are doing . If your score is 80% or higher you will see your score, and you can go on.