A 4-digit lock typically uses digits from 0 to 9. Each digit in the lock can be any of these 10 digits. To find the total number of possible combinations, you multiply the number of choices for each digit.
For the first digit, there are 10 possible choices (0-9). Similarly, the second, third, and fourth digits each have 10 possible choices. Therefore, the total number of combinations is calculated as follows:
10 (choices for the first digit) × 10 (choices for the second digit) × 10 (choices for the third digit) × 10 (choices for the fourth digit) = 10,000 combinations.
So, there are 10,000 possible combinations in a 4-digit lock.