A small combination lock on a suitcase has 4 wheels, each labeled with the 10 digits from 0 to 9 . If an opening combination is a particular sequence of 4 digits with no repeats, what is the probability of a person guessing the right combination? The probability of a person guessing the right combination is (Type a fraction. Simplify your answer.)

Step 1 ：A small combination lock on a suitcase has 4 wheels, each labeled with the 10 digits from 0 to 9. If an opening combination is a particular sequence of 4 digits with no repeats, we are asked to find the probability of a person guessing the right combination.

Step 2 ：The total number of possible combinations is \(10*10*10*10 = 10000\) since there are 10 digits (0-9) and 4 wheels.

Step 3 ：However, since the problem states that there are no repeats in the combination, the number of possible combinations is \(10*9*8*7 = 5040\).

Step 4 ：The probability of guessing the right combination is therefore 1 out of 5040.

Step 5 ：Initially, the probability was calculated as 0.504, which is incorrect. The probability should be 1 divided by the number of valid combinations, not the number of valid combinations divided by the total number of combinations.

Step 6 ：Correcting the calculation, the probability is \(\frac{1}{5040} = 0.0001984126984126984\).

Step 7 ：Final Answer: The probability of a person guessing the right combination is \(\boxed{0.0001984126984126984}\).