Group competition to help students practice their basic facts. The cost is $1 per month per student. Students solve basic math facts + - x / on a timer. The faster they solve the problem the more bases they get. The timer starts at homerun and goes down to single as time passes. If time runs out or the student answers incorrectly the student would be out.
The NCTM website has excellent ideas for lesson plans, interactive on-line math activities, challenge problems, and more. NCTM offers many professional development resources such as journals, on-line conferences, information about regional conferences, an