Arithmetic help

[philomina]

Can anyone please help me with this question.

How many different four digit numbers are there if no digit is repeated?
Answer options are:
a) 4
b) 24
c) 504
d) 4536

 

[Denis]

Each leading digits 1 to 9 (0 can't be a leading digit, I assume) produces 9! / 6! 4digit numbers.

If that's not enough, then you need help from your teacher.

 

[Deleted member 4993]

Can anyone please help me with this question.

How many different four digit numbers are there if no digit is repeated?
Answer options are:
a) 4
b) 24
c) 504
d) 4536

The first digit - 1000 th position - can be filled with 9 numbers (0 not allowed) ................. ..............................9 ways

The second digit can be filled with 9 numbers (any number except the number chosen above)..............................9 ways

The third digit can be filled with 8 numbers (any number except the numbers chosen above)..............................8 ways

The third digit can be filled with 7 numbers (any number except the numbers chosen above)..............................7 ways