RODD:We're going to need a little mathematical ... That's subtraction! You rock! NARRATOR:'Attention, attention, Number Squad. Find a space and move with Rodd.' RODD:Okay, new game.

Percy Liang at Stanford. The last player to move the "rock" into the end position wins the game. This can be modelled as a subtraction game - assume we start with a number 25 and either player can ...

Children can play online math games that help them with addition, subtraction, multiplication, division, decimals, money, and more. CoolMath is geared toward ages 13 and up, but sister site ...