KenKen Puzzles Online — Sum Cages for Kids 6+

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KenKen puzzles (also called Calcudoku or Mathdoku) are sudoku with arithmetic inside: a grid where every row and column holds each number once, cut into outlined cages, and each cage shows a target and a sign — '6+' means the two numbers add to six, '12×' means they multiply to twelve.

Here it is Sum Cages: 500 puzzles from a 3×3 with plus only up to 6×6 with no signs at all, where the child has to work out which operation fits. Every puzzle is machine-checked to have exactly one solution, so it is always solvable by reasoning, never by guessing.

No timer, no lives, no hints that give the answer away: the board only marks a real rule break — two equal numbers in a row, a cage that already overshoots its target.

How to play

Tap a cell, then a number on the big keypad; tap again to erase. Switch on the pencil to jot candidate numbers into a cell. The first puzzle is a voiced lesson on the live board, and every new sign gets a one-time card before it appears.

Big Undo is always at hand; Restart asks first, so a whole board is never lost to a slip of the finger.

What your child learns

Each cage is a tiny arithmetic problem — 'which two numbers from 1 to 4 make 5?' — solved hundreds of times in a row without feeling like drill. Children practise addition and subtraction facts, then multiplication and division, and on top of that learn to reason: 'this cell cannot be 3, because 3 is already in this column'. Number facts and logical deduction in one game.

The science behind the games

Every Dad4Kids game is built on one simple truth: children want to play, not study — so we turn learning into a game worth replaying. The method draws on peer-reviewed research in game-based learning, motivation, and how memory works.

FAQ

Is this the same as KenKen?

Same rules — KenKen is a trademark of a puzzle company, so the game is called Sum Cages here. The puzzles work exactly the same way.

Does the game show which numbers are right?

No. It only marks a broken rule — a repeated number in a row or column, or a cage whose sum is already too big. Whether a number is correct you find out by finishing the grid, like on paper.

Which grades is it for?

3×3 with addition suits a six-year-old; 5×5 and 6×6 with multiplication and division are a real challenge for 3rd–5th graders.

Is every puzzle solvable?

Yes: every one of the 500 puzzles was verified by a solver to have exactly one solution.