This is a simple set of Matching cards that looks at a series of rearrangements. There are two formulae which could be a rearrangement of each other and then one that is the odd one out. Sets of these can be cut out and put into individual bags for a starter activity in pairs and groups. It has been designed to generate discussion about rearranging and the rules that apply. I have used it with GCSE and my Year 9 high ability group.