Many children concentrate much more on the colouring than on the mathematical concepts, so I would like to give you the following ideas:

• Give the class an A4 piece of paper
• What shape is it?
• Fold it
• What shape is it?
• Can you make it into a square
• Fold it this way
• What shape have you? A triangle
• Open it back to a square
• Fold down 1 corner
• What shape is it now? A pentagon
• Fold for 6 sides etc

It is really important that children see irregular pentagons and hexagons and that their only experience is not the shapes in the 2D shape box.

Next idea - we all presume that children know the properties of a square but I recently gave my Y1 class some dotty paper they could easily draw the smallest square, but as the square became bigger they found this really difficult.

On dotty paper, you draw one side of a square (eg 6 dots) and ask them to complete the square. I think you will be really surprised at how few children can do this.