Question

How many 10 digit numbers can we make with 5,342,781?

Answer 1

You provide 7 digits and require a 10 digit number. So it is imperative to have repetitions. I will assume that any of the seven digits can be chosen and any repetitions are allowed.
Choice for the first digit: 7
Number of one digit numbers : 7
Choice for the second digit : 7
Number of two digit numbers : 7*7 = 7²
Choice for the third digit : 7
Number of 3 digit numbers : 7*7*7 = 7²

Can you continue till 7 digits?

Answer 2

Thank you. I thought the question was off.

Answer 3

It is a little adventurous to interpret it this way, I admit. In any case, this is the best interpretation I could make out of the question!