A teacher asks each student to pick a four or five digit password using the numbers 0 to 9. If repetition is not allowed, how many different passwords are possible?
4 digits
1st :10
2nd : 9
3rd : 8
4th : 7
4 digit password= whatever 10x9x8x7 equals
5 digits
1st :10
2nd : 9
3rd : 8
4th : 7
5th : 6
5 digit password= whatever 10x9x8x7x6 equals
Is this right?