When you start this activity, students receive a Venn diagram of real number sets (natural, whole, integer, rational, irrational)on their calculator. This same diagram is projected on the Activity Center screen at the front of the room. The teacher writes a value on the board and students move their cursor to the correct part of the diagram.
Before the Activity
Students should be familiar with the definitions of the number sets.
During the Activity
The activity requires a prepared list of values to be used by the teacher. Values are displayed one at a time on a white board or wherever students can see it (as long as it does not interfere with viewing the activity center screen).
Suggested list:(1)[-12,integer] (2)[2/3,rational] (3) [-7.8,rational] (4)[square rt(5),irrational] (5)[345, natural] (6)[0.1111...,rational=1/9] (7)[2.2360679..., irrational=sqrt(5)] (8)[0,whole] (9)[3.14, rational approximation of pi] (10)[Pi,the greek symbol for the irrational value] (11)[-6/2,integer=-3] (12)[square rt(81),natural=9] 13)[square rt(-6),trick question!not real]
As students move around the diagram, give hints and see how students who are in the wrong place react.
Try turning the projector off and forcing them to do the problem looking only at their own calculator, then turn it on to reveal what the class as a whole was thinking. Teach and re-teach as needed.
After the Activity
Note: An activity like this was described in the TI - Navigator for Dummies book