Logic Masters Deutschland e.V.

In my first ever published puzzle I used alternating sums to disambiguate the solution without giving too much away early on. Here the interaction of alternating sums and arrows are the main idea of the puzzle.

• Normal arrow sudoku rules apply (normal sudoku rules apply and numbers on an arrow sum up to the number in the attached circle).
• On the blue line the outer digits sum to the central digit.
• Numbers outside the grid give the alternating sum of that row/column. The alternating sum is calculated by alternately adding and subtracting numbers (e.g. if you have a row of 873 614 529 - in that order - ist alternating sum is 8-7+3-6+1-4+5-2+9 = 7).
• The numbers within cages - read from left to right or from top to bottom - are divisible by the clue in the top left corner (for dividibility rules look below the puzzle). Note: it's not about the sum of the digits in the cage but just the number read as a decimal number in this cage.

• A number is divisible by 3 if its digital sum (=sum of all digits) is divisible by 3.
• A number is divisible by 11 if its alternating sum is divisible by 11.