Great handout to scaffold students while practising this tricky concept. It begins with a detailed explanation of how to find the Greatest Common Factor of a set of numbers then the pages gradually increase in their level of difficulty.
This is also great for marking if you're like my school and using outcome based reporting! If students cannot complete the first couple of pages they are not yet meeting the outcome. If students are successful with pages 3 and 4 they are achieving the outcome. And if they are able to successfully complete the final page they are excelling the outcome.