Logic Masters Deutschland e.V.

Enter a number from 1 to 9 into each white cell. The numbers in grey cells indicate the sums of the numbers in the horizontally or vertically adjacent "words". Within each word, no number can appear more than once. (note that even if a "word" doesn't have a given sum, numbers still cannot appear more than once within it)

Also, 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.)

Interactive version available "here"