This puzzle consists of a 3x3 grid of squares containing the numbers 1-9.
For any given square, if you take the sum of the numbers in the same column and the numbers in the same row, the last digit of the sum will be equal to the number in the square.
You can only use each number once.
You can only use numbers.
Based on certain criteria, a cell may turn to a different color than normal. Here is a guide to the meanings of the different colors:Blue: This color indicates that the puzzle does not understand the contents of the cell, this means that you likely typed something other than a number between 1-9. Red: This color indicates that you have used the number in this cell more than once. This is not allowed, and you should fix the number to be unique to that cell. Green: This color means that the cell's criteria have been met. The number in the cell is the last digit of the sum of the other cells in the same row and column. This cell is complete.
The interface includes a notes panel that you can use to record your notes as you work on the puzzle. You can press the "Notes" button in the menu to bring up a panel to the side of the puzzle. The notes panel will not appear on a screen smaller than 800 pixels in width.
All puzzle information and notes are continuously saved. You do not have to worry about losing your work when you close the window.