Every row and every column holds the numbers 1 to 4, each exactly once, as in Sudoku.
The thick lines outline cages. The top left of each cage shows its task: 5+ means the numbers in the cage add up to 5. 2− means their difference is 2. 6× means their product is 6. A cage with a single square already gives away its number.
Start with the cages that only a few numbers fit: a two-square 6× cage can only hold 2 and 3, a 3+ only 1 and 2. Then the Sudoku rule helps with the remaining squares.
Example
For parents
What does this exercise practice?
Number decomposition becomes a tool: which numbers add up to 5, which have the product 6? Added to that is elimination, as in Sudoku. Every grid has exactly one solution, so guessing is never needed.
Common pitfalls
Two numbers in a cage may be the same if the squares do not share a row or column, for example in an L-shaped cage. With minus only the difference counts: 2− fits 1 and 3 in either order.
How to practice at home
A game with four coins or cards (1 to 4) on the table: who finds two cards that add up to 5, and two with a difference of 2? That way you practice all the number pairs before the grid begins.
Related: Logic grid, Find the Rectangles