Large print Calcudoku: Sudoku with sums
Calcudoku mixes the row-and-column rule of Sudoku with a little adding up. There are no boxes. Instead, heavy lines divide the grid into cages, and the small number in the corner of each cage is the total that its numbers must add up to. Every row and every column holds each number once: 1 to 9 on the large grid and 1 to 6 on the small one. A number may repeat inside a cage only if its squares are not in the same row or column, which can happen in a bent cage.
A square that sits alone in its cage is simply a given number, shown in heavy type. Nothing here asks you to multiply, divide or subtract: you only add small numbers, and the cage totals do the work that the boxes do in Sudoku. The numbers are big and bold, the cage lines are heavy and the totals are printed large, and you can enlarge everything with the text size buttons.
How the levels differ
The levels change the cages, not the size of the grid. Easy has small cages of one or two squares, with plenty of numbers given. Medium has cages of up to three squares and fewer given numbers. Hard has cages of up to four squares and few given numbers, and asks you to weigh which numbers can make a total. Every puzzle has exactly one answer. Easy and Medium can always be finished by finding the one square where only one number fits, and even Hard never needs a guess.
Two sizes
The 9 by 9 grid is the full-size puzzle, and the 6 by 6 grid is a gentler one with bigger squares. The free Calcudoku each day is the 9 by 9 Easy, and members will be able to play both sizes at every level. The same puzzle design is used for both, so a 6 by 6 Hard is a short, sharp puzzle and a 9 by 9 Easy is a long, relaxed one.
Hints, undo and saving
If you are stuck, press Hint. The first press highlights the cage that holds the next move, and a second press fills the number in. Hints only change the stars you earn: three stars for none, two for one or two, and one for three or more. The time you take never lowers your stars, and Zen Mode hides the timer. Undo is always one press away.
Your progress is saved on your own device after every move. Free players keep it there; members will be able to play unlimited puzzles every day, and their scores and history on every device. New to grids like this? Start with the guide to solving Sudoku, which explains the row and column moves that Calcudoku uses too.