The numbers of ways in which we can arrange the digits 0-9 in such a way that each digit can be used only once is:
10!
( since the total number of digits from 0-9 is 10
so we have to arrange these 10 digits in order such that repetition is not allowed
so let in first place we can have any of the 10 digits.
then in second place we can choose out of the remaining 9 digits.
for third place we can choose any of the remaining 8 digits and so on till the final place so the arrangement will be:
10×9×8×7×6×5×4×3×2×1=10!=362800
)
