Question

How Many no. Between 1000 to 9900 in which four digits of number are different

Answer 1

you can start counting

Answer 2

ha ha

Answer 3

jk, sorry cant help with this one

Answer 4

When you say different - do you mean have no repeated digits?

Answer 5

I think you are asking for derangements.
http://en.wikipedia.org/wiki/Derangement

Answer 6

8900

Answer 7

Number of 4 digit numbers having all different digits = 9*9*8*7 = 4536
smallest number : 1234, largest number : 9876, all are between 1000 and 9900.


ans: 4536