Mathopoly Games Presents The One! Except, in this case you don't want to be... The One. Students will use their mental math subtraction skills to try and find the magic number needed to always come ahead the winner. Subtraction rules change with every game, sometime you can subtract 1 or 3, sometimes its 1,2 or 4 and so on. This fun activity of striking off character Bailey using subtraction skills and counting ahead is a hit with kids...and adults.