is a square grid of 3 x 3 or 4 x 4, whose cells are to be filled by some digits. The task is to fill additional digits in required cells such that the sum of numbers in each row and each column equals to 100. The puzzle book contain: - 200 Puzzles - Handy 6 x 9 inch Book Layout - 2 Puzzles per Page - Ideal for both Beginners and Experts In the book you will find a description and examples of solutions for all puzzles. The book is for those who like logic and math problems. Decide, developing and improving.