Fill the grid with the digits 1 to 9. The number in a cell must be the sum or the difference of the numbers in the both cells below the number. Each gray row has no repeated number. Each white row has at least one number that is repeated.

Fill the grid with the digits 1 to 9. The number in a cell must be the sum or the difference of the numbers in the both cells below the number. Each gray row has no repeated number. Each white row has at least one number that is repeated.

Fill in the grid so that every row, every column, every 3x3 box and both diagonals contains the digits 1 through 9. The algraic operations in the cells must be fullfilled.

Fill in the grid so that every row, every column, and every 3x3 box contains the digits 1 through 9. Each clue-number is the product of the two neighbored digits.

Fill in the grid so that every row, every column, and every 3 x 3 box contains the digits 1 through 9. The specified numbers are equal to the product of there horizontally and vertically adjazent cells. (There is no extra constraint that they must be different.)

Fill in the grid so that every row, every column, and every 3x3 box contains the digits 1 through 9. Some rows and columns have numbers. They represent the product of the two ends.

Fill in the grid so that every row, every column, and every 3 x 3 box contains the digits 1 through 9. Digits in the outside frame equal the product of the three numbers of the corresponding row or column in the contigious box.

Fill in the grid so that every row, every column, and every 3 x 3 box contains the digits 1 through 9. The product of the digits within each sub-region is equal to the specified number.

Fill in the grid with the digits 1 through 9. Each number should be used only once. The number in the coloured square is the sum of the four adjazent cells. The arrows show the biggest of the four adjazent digits.

Fill in the grid with the digits 1 through 9. Each number should be used only once. The number in the coloured square is the sum of the four adjazent cells. The arrows show the biggest of the four adjazent digits.