Answer:
There are 10,000 possible lock codes.
Each digit on the lock can be any number from 0 to 9. Since the lock uses 4 different numbers, there are 10 choices for each digit. This gives us 10 x 10 x 10 x 10 = 10,000 possible combinations.
For example, some possible combinations are 0123, 4567, 8901, and 9876.
Note that the order of the digits matters. So, 1234 is a different combination from 4321.
Explanation: