I.T. Kid

A board of coloured, numbered tiles and a target figure beside it. Numbers is FreeOnlineGames' 2009 puzzle game, and its rule is a small arithmetic one stated plainly on its own instructions screen: click any group of blocks that add up to the number on the right of the screen. Clear a group and the board refills or shrinks; run out of ways to reduce the target and the round is over.

A countdown sits in the corner and the score beside it, so the game is a race as much as a sum -- spot a set that totals the target, click it, and move before the clock empties. When the board finally beats you there is a Game Over screen with a Play Again button and a high-score board behind it. It is bright, brisk and built for a few minutes' play.