We all need to like and use more math in a high tech society and future. We do not want be behind the robots but ahead of the showing them the way. This is a great new math activity and educational book. It is our humble effort to spread the use of math. This book is excellent for all ages 8 and higher. It has 400 numerical and geometrical exercises. Four problems to a page. Each exercise blends solid geometry, triangles, numbers and algebra and can be solved using different approaches. The most interesting approach is guessing a numerical solution then improving on it. In each problem a tetrahedron/TetraTri is given with 4 pieces of information and four other numbers that need to be found. We call this approach reverse math. In "regular" math you can add two numbers easily. But in our approach it is like given a number, can you find where it came from. Teachers can use this book for bonuses/extra credit, homework, contests and as a IQ samples. This is also a good way to sharpen your brain as you get older. Reader does not need answer sheets because (s)he can check own answer to make sure it fulfills the criteria given. This book follows in the same steps of the author's other ground breaking books JUGGLE 3, PENTAGON STAR, THE HIGH 5, ADDITION ADDICTION, MULTABLE, NEXT NEIGHBOR NUMBER NNN, THE HALVE(S) AND HALVE(NOT)S and HODOKU. Author welcomes all reviews, suggestions and discussion in the hope to improve on the products to serve an extended base of readers and users in and out of schools. Be tuned for more books and games from Omar Minyawi enterprise.