Normal sudoku rules apply. Some circles contain a maths operator (+,-,x,/). If you apply that operation to each pair of diagonal digits touching the circle then you'll get the number in the circle as the result BOTH times. A circle with a ? instead of number indicates that the result is the same for both pairs of digits but must be deduced. If a circle does not contain an operator, the digit(s) in the cirlce must appear in at least one of the cells touching the circle.
If you prefer to play directly in sudokupad then click below.
