24
Twelve of them.
4*3*2*1 = 24
64 if repetition is allowed.24 if repetition is not allowed.
256
24
Twelve of them.
smallest=1234 greatest=4321
4 x 3 x 2 ie 24
4*3*2*1 = 24
1234, 2637, 7777, 2727 are examples of a four digit number. So any random four numbers are four digits.
There are 4^6 = 4096 such numbers.
64 if repetition is allowed.24 if repetition is not allowed.
256
That would be 4! = 4 * 3 * 2 * 1 = 24
1234
a 8-digits palindromic number is a number consisting of a 4-digits number written and then written backward, i.e. 1234 4321 so there are as many palindromic 8-digits numbers as 4-digits numbers so from 1000 to 9999, so there are 8999 palindromic 8 digits number (I assumed that 00011000 is not to be considered as a valid 8 digit number)