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Ruth has glued 2009 unit cubes together to form a cuboid. She opens a pack containing 2009 stickers and she has enough to place one sticker on each exposed face of each unit cube. How many stickers does she have left?

If you liked this problem, here is an NRICH task which challenges you to use similar mathematical ideas.

*This problem is taken from the UKMT Mathematical Challenges.**View the archive of all weekly problems grouped by curriculum topic*