I love this Illustrative Mathematics, OpenUpResources lesson launch from Grade 7 Unit 3 Lesson 3), it's visual and inevitably creates healthy debate and curiosity! While listening to students engage in conversations, questions, guesses, and wonderings I happen to be holding a paper tube and started to wonder myself, could we show or prove which is greater without words or measuring? Below is a short video what do you notice?

WORKSHOP OPPORTUNITY!!!