The 30 Second Challenge system has been written to build-up gradual, step by step improvements in your understanding and memory of number facts. The puzzles found in our newspaper columns, e-books and games provide an entertaining approach to developing mental arithmetic skills. Spend 15 minutes each day tackling the carefully graded challenges and, in no time at all, you will be able to perform mental gymnastics quickly and accurately.
The 3 Level Challenge E-Books are collections of fun challenges for adults and children to improve their mental arithmetic skills. Each e-book contains 48 challenges at Beginner, Intermediate and Advanced levels, making a total of 144 challenges per e-book.Shop Now