How many 5-digits numbers can be formed using digits 0-9 if repetition is allowed?

Five-digit numbers will have places as follows.

1st place can be filled up in 10 ways.

2^nd place can be filled up in 10 ways.

3^rd place can be filled up in 10 ways.

4^th place can be filled in 10 ways.

5^th place can be filled in 9 ways as if 0 will be there the number will be a 4 digit number.

So total no of ways to make 5-digit number is:

9× 10× 10× 10× 10

= 90000 ways