This post is a link to https://naturalmath.com/five-fabulous-activities/

With Paul Ellis and Japheth Wood. Natural Math, publisher.

Abstract: Math circle activities are often interactive, exploratory, flexible, open-ended, and social. This might sound like a really fun idea, but how does one make it happen? Five fabulous activities for your math circle will show you how. This book is a guide and a collection of recipes for anyone who wants to help others discover joyful and challenging math. Our book will help you guide mathematical learners of a wide variety of ages. We primarily target middle and high school students. We have also included activities and explanations intended for younger math friends. The underlying mathematics can be of interest even to adult learners, including ourselves!