• 100 or 0
Skill Application: Using the abacus for addition or subtraction. Also reviews tallies and estimating.
Object: To reach 100 (if adding) or 0 (if subtracting) by the exact number, and to do it in the amount of estimated rolls of the dice.

Materials:

• Abacus
• 2 dice
• Materials to record tallies

To Play:

• Decide whether to practice addition or subtraction. If practicing addition, leave the abacus set at 0. If practicing subtraction, set the abacus to 100.
• The player then makes an estimation of how many rolls of the dice it will take to get to the goal of 100 or 0.
• The player records a tally before each roll of the dice.
• The player rolls the dice and either adds or subtracts the numbers on the dice. (Since the player must get to 100 or 0 exactly, this decision becomes important toward the end of the game.)
• The game ends when the player reaches the goal of 100 or 0 with the exact number.
• Count tallies to see how close the player was able to get to his/her estimate.