After reading and discussing Two of Everything, model the Magic Pot Game that students will play in pairs:

Materials (per pair of students):

• Magic Pot template in sheet protector
• dry-erase pen and eraser
• index cards with Magic Pot rules
• 20-30 linking cubes in two colors
• magic pot or Magic Pot mat

Directions:

• Partner A chooses one of the Magic Pot rules.
• Partner B places a couple of linking cubes (all the same color) in the magic pot or on the magic pot mat and records that number under IN on the Magic Pot Template.
• Partner A adds linking cubes (of the second color) to those cubes according to the Magic Pot Rule.
• Partner B records the total number of cubes (sum of both colors) in the OUT column on the Magic Pot Template.
• Partner B may guess the rule by writing the rule on the Magic Pot Template. He/she must then check the rule by placing a different amount of cubes in the magic pot. He/she should record this number under IN on the Magic Pot Template. He/she should also record the OUT number that follows the rule.
• Partner A adds linking cubes (of the second color) to those cubes according to the Magic Pot Rule.
• If Partner B's rule and OUT number were correct, Partner B scores 5 points for correctly guessing after the first try.
• If Partner B's rule is NOT correct, Partner B corrects the data in the IN/OUT table and tries a different IN number.
• Partners score 1 less point for each incorrect guess.
• When Partner B correctly guesses the rule and proves it by writing a different IN/OUT combination that works with the rule, Partner B scores points and the partners switch positions.
• Winner has the most points after 3-5 rounds or when the allotted time is up.

from:

http://www.mathwire.com/games/algebragames.html