Normal sudoku rules apply. In cages, digits cannot repeat. The digits in each cage sum to the “cage total”. Clues outside of the grid (“Sandwich totals”) are the sum of the digits between the 1 and 9 in their row/column. In every row and column containing a “?”, the sandwich total will be equal to one of the cage totals in that row/column. Nothing is known about rows/columns with no ? clue. EG Row 7's sandwich total is either equal to the cage total from column 1's 7-cell cage, the 8-cell L shaped cage in column 2, the 4 cell cage in column 3, the 2 cell cage in Box 8, the 5 cell cage in boxes 5/8, or the 9 cell cage in boxes 8 and 9.