 This is a mathematical snack from the Association of Teachers of Mathematics. So here I have two pieces of the same size paper. I'm using A5. Folding the short edges together and then press firmly along the edge to form a crease. Open this out and then fold the edges towards the middle, press firmly and form another crease. When this is done, use a bit of cellotape down the middle to keep the edges together. Open up the shape you've made and now you can see that stood on its end it forms a cuboid. Now repeat this using the other piece of paper, folding it in half and matching the long edges. Remember to press firmly to get a good crease. Here are my finished cuboids. The yellow and green are cuboids made in the same way but using A4 sized paper. The task is to find out which of the pair holds the most. Here are some things you might have available to help you. I'm using milk bottle tops.