The question does say you know the numbers but not the order, otherwise you would be (almost) correct. There would be 10x10x10x10 = 10,000 combinations (you must have forgotten 0000).
I'm guessing that there are four rotating bezels each with 0 to 9 (ie 10 digits). The possibilities are 10 to the power of four. That is 10 x10 x10 x 10 ie 10,000 possibilities.
So, to sum up - there are 10,000 combinations in total but there are 24 that contain the known 4 digits, if they are all different, which maybe what katiesara was asking.
I would like to revise my previous answer. If you know the four digits, but not which order they are in, it is similar to having 4 dials each of four numbers. The total number of variations is, therefore, four to the power of four (4 x 4 x 4 x 4) = 256.