Math regrouping

Hundred zap
To teach students when to regroup.
Put students in pairs. Give each student ones blocks, base ten rods, a hundred flat, one die, and a meter stick.
Students take turns rolling the die and adding cubes (numbers). When cubes equal ten students exchange cubes for a ten rod.
If student forgets to regroup before giving die to other player, other player can call zap. The student has to remove all tens and ones thus starting over.
First player to reach one hundred wins.