Fill in numbers from 1 to N (N is the size of the grid) such that there are no duplicates in rows or columns. Circles at intersections have a mathematical operation and a total that is the result for each pair of diagonally adjacent cells.
Fill numbers in the grid to create a single path that forms a sequence from 1 to the highest possible number. Only orthogonal movement is allowed.
Fill the grid with the numbers 1-9 such that there are no duplicates in any row, column, or 3×3 region. At the bottom of this tutorial are several variants for which the solving process is basically the same.
