Download or read book CalcuDoku Puzzles - 400 Hard to Expert 9x9 written by Alexander Rodriguez and published by Createspace Independent Publishing Platform. This book was released on 2018-05-21 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt: Each puzzle consists of a grid containing blocks surrounded by bold lines. The object is to fill all empty squares so that the numbers 1 to N (where N is the number of rows or columns in the grid) appear exactly once in each row and column and the numbers in each block produce the result shown in the top-left corner of the block according to the math operation appearing on the top of the grid. In CalcuDoku a number may be used more than once in the same block.