About CalcuDoku GameCalcuDoku is a combination of a Sudoku game with arithmetic puzzles. Select the difficulty level you would like to play from easy, normal, hard, and expert. Easy puzzles are a 3x3 grid and each level of difficulty increase also increases the puzzle grid size to where expert puzzles are a 6x6 grid. On each puzzle you must include each of the numbers once in each row and once in each column. If you enter the same number twice in a row or column the cells with duplicate numbers turn red. There are arbitrary groupings in the puzzle which contain a solution and an arithmetic operator. The same number can appear multiple times in an arbitrary grouping. The numbers you enter must satisfy the given solution with the associated math operator. Puzzles are timed. It is best to start on easy until you get the hang of the puzzles & then play more challenging levels. When starting puzzles it is best to go with the smaller groupings first as their list of potential solutions are smaller. Single-cell groupings are a given, though you still have to type in the numbers. Tap into a cell then click on the number you want to enter. Press the X to remove a number, or tap the lightbulb for a clue for that cell, which costs you 5 seconds. Fill in the grid correctly before the timer runs out to beat each puzzle. This is a JavaScript web application which uses cross-platform mobile-friendly HTML. All modern web browsers like Microsoft Edge, Apple Safari, Google Chrome, Mozilla Firefox and Opera should support it. This game works on just about any type of computing device including Microsoft Windows desktop computers, Apple OSX Mac computers, iOS powered tablets and phones like the iPad and iPhone, laptops like the Google Chromebook, and the many types of mobile phones from manufacturers like Samsung which are powered by Google Android.