100 Math Brainteasers (Grade 7, 8, 9, 10). Arithmetic, Algebra and Geometry Brain Teasers, Puzzles, Games and Problems with Solutions Paperback – November 16, 2021

This is an enjoyable collection of puzzles, marred by low publishing standards.On the positive side, it's a varied mix of original problems, divided into five sections such as equations, geometry, and integers. Some take just a flash of insight, others require sharpening your pencil. Anyone with a casual interest in math will probably enjoy them; if you have a college degree in math, this book probably won't be enough of a challenge.But: Navigation on Kindle is terrible. Answers are not text, but an image of the text. To find an answer you must go to the contents, then to the answers, then page through; you can't search. Furthermore, this text is too small to read easily; if you enlarge it, it just gets blurry. I found it best to answer a half-dozen questions, then make my way to the solutions section.The book apparently was translated from Polish. Phrasing (especially in the solutions) is sometimes convoluted, and occasionally ambiguous.

I am an adult working through these problems for fun. Unfortunately it has been more of a frustration than fun. The problems are written in a convoluted way and the solutions are explained in an even more convoluted way. Some are plain wrong as for example the one for problem 16. Maybe it is a problem of translation from Polish and on my next visit to Poland I will check it out. Don't subject your kids or yourself to this confusion.