Place a nonzero digit into some of the white cells of the grid. Shaded cells must remain blank. No digit can repeat in a row or column. In each row, the sum of the digits must be equal to some fixed value R (which you find during the solution). Similarly, in each column, the sum of the digits must be equal to some fixed value C. Circles in the grid give all the digits in the cells that touch the circle. (Including repeats; if two cells touching a circle have the same digit, the circle must co...
