Kendoku

Rules

Fill the grid so that every column and every row contains the digits 1 up to the largest number (which always equals the number of cells per row). The numbers in each bold set of squares, called cages, must be combined in any order using the mathematical operation indicated and as a result thereof leading to the target number in the top left corner. Within a cage a number can be repeated as long as it is not in the same row or column.