If you feel that your children's angle-finding skills would benefit from just a little more practice, have a look at this Year 6 Angles in Polygons extension resource. It's designed to be used as an in-class extension or homework, and is differentiated three ways to give you flexibility. With two varied fluency questions and a reasoning question at every level, it's a great way of solidifying your children's knowledge, or checking that they've really grasped the topic.
The pack comes with an answer sheet too. Handy for speeding up marking time, or for helping your class to self- and peer-mark their work!