Having trouble loading the game? We're hard at work updating our games from Flash to HTML5; in the meantime, if you are stuck waiting for the game to load, please be sure to check if Flash is enabled on this page. DriverEasy.com has an excellent guide here.
Be sure to add www.thinkfun.com and beta.thinkfunbrainlab.com to the 'allow' area on your browser's Flash settings.
Easy – Subtract then Multiply