In mathematics, we have been developing our mathematical thinking by investigating perimeter. When we removed one square from a rectangular grid it increased the perimeter by 2cm. Many of us conjectured (said what we thought would happen) that for every square removed the perimeter would increase by another 2cm. We investigated this further and proved our conjecture to be incorrect. It was great fun! Several children enjoyed this challenge so much that they continued to investigate this problem at home.