What this exercise trains
The familiar 9x9 grid: each row, column and 3x3 box holds the digits one to nine exactly once. Tap a cell, pick a digit, and wrong entries are flagged as you go.
Sudoku rewards systematic deduction and working memory for constraints, and every puzzle here is solvable without guessing. It is a genuine logic exercise, though research on whether puzzle practice raises general reasoning is mixed at best — getting better at Sudoku mostly makes you better at Sudoku.
Training exercises are not a scored assessment. For a measured result across four reasoning domains, take the free IQ test, and see our methodology for how that score is worked out. More exercises are on the training page.