This one isn't so much maths as it is logic. Hope that's alright.

Bellow is a picture of fifteen gnomes divided into parts:

http://i204.photobucket.com/albums/b...n/15Gnomes.png

Rearranging the top two parts gives the following picture of forteen gnomes:

http://i204.photobucket.com/albums/b...n/14Gnomes.png

The question is: 'Why are there more gnomes in the top picture then the bottom?'