Logic Masters Deutschland e.V.

Rules:

• Standard Sudoku rules apply.
• Digital Root Arrows:
  The bulb must contain the DIGITAL ROOT of the sum of the digits along the arrow.
• Digital Root Killer Cages:
  The number in the upper left corner of the cage (if given) indicates the DIGITAL ROOT of the sum of the digits in the cage.
• Digital Root Little Killer Sums:
  The digit sums of diagonals indicated by like-colored arrows outside of the grid MUST have the same digital root. The value corresponding to each color is left for the solver to discover, and they are not necessarily distinct.

(rules end here - explanation of digital root below)

To get the digital root of a number, sum its digits, and if the result is still more than one digit, repeat the process with the new number until a single digit result is reached.

Example: if an arrow (or cage) contains the the digits 4,7,8, then the sum is 19, and the digital root of that sum is obtained by first adding the digits of 19 to get 10, and then adding the digits of 10 to get 1. So the digit in the arrow bulb (or the cage number if given) would be a 1.

Play Online:

     f-puzzles: Digital Roots

     ctc: Digital Roots