Enter a single digit from 1 to 9 into each white cell so that the sum of digits in each Across entry equals the value in grey to the left of the entry (if given), and the sum of digits in each Down entry equals the value in grey above the entry (if given). No digit may be repeated within a single entry. A white circle between two cells shows that the digits in those cells are consecutive (i.e., they differ by 1). A black circle shows that the digit in one of the cells has twice the value of the other. If there is no circle between adjacent cells, neither of these properties holds. (Note: between 1 and 2, either a white or a black circle can be given.)