{"product_id":"hard-to-very-hard-calcudoku-puzzles-6x6-book-for-adults-200-puzzles-at-the-level-of-hard-to-very-hard-9798703264041","title":"Hard to Very Hard Calcudoku Puzzles 6x6 Book for Adults: 200 Puzzles at the Level of Hard to Very Hard","description":"The book contains 200 Calcudoku puzzles 6x6 at the level of Hard to Very Hard. Hard puzzles 100, Very Hard puzzles 100. All riddles have only 1 solution. 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.\u003cbr\u003e","brand":"Independently Published","offers":[{"title":"Default Title","offer_id":51720846934290,"sku":"9798703264041","price":7.99,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0831\/4771\/8930\/files\/img_39244b84-b5bc-4f3e-8319-5841da9a9768.jpg?v=1762938492","url":"https:\/\/surprise-castle.myshopify.com\/products\/hard-to-very-hard-calcudoku-puzzles-6x6-book-for-adults-200-puzzles-at-the-level-of-hard-to-very-hard-9798703264041","provider":"Surprise Castle","version":"1.0","type":"link"}