5All the challenges in this entertaining puzzle book are the same. Fold the corner of the paper to a given dot and find the folded area. A small move of the target dot can drastically change the logic needed to find the solution to the challenge. The problems become increasingly complex as the book progresses, with possible solutions involving Pythagoras' and similar triangles as well as trigonometry and algebra. However, insights learnt from earlier challenges can help with those that follow. If at any point the challenge becomes too great, the answers can always be found by measurement with a ruler and directly calculating the area. The book encourages curiosity, a "find out what you can" approach that creates interesting and varied solution strategies. The aim is that deep thinking and geometrical reasoning can come out of exploring and discussing the paper folds. The challenges are for all ages (10 years and over). Thus, for teachers the book provides a rich source of challenges that have a similar appearance, yet hide an obvious method and require students to choose how to approach the problem. Comparing solution methods when checking the answers is also useful as the solutions highlight some fascinating facts linked with these simple folds.