Normal sudoku rules apply. Additionally, there are some empty cages in the grid. In these cages, digits do not repeat, and somewhere within them is their cage total i.e. their sum, which is always two digits next to each other, read left to right or up then down as a 2 digit number. It is up to the solver to determine what each cage's sum is. Consecutive cages (ie cages that share an edge) cannot sum to 63.