The first digit can have 5 possible numbers, the second digit can have 4, the third 3, the fourth 2.
5
1 set
125
There are 60480 numbers.
There are 5! = 120 such numbers.
90000. With 10 digit palindromes, the last 5 digits are the same as the first 5 digits in reverse, eg 12345 54321. So it comes down to how many 5 digit numbers are there? They are the numbers "10000" to "99999", a total of 99999 - 10000 + 1 = 90000.
1 set
It is 120 if the digits cannot be repeated.
If repetition of digits isn't allowed, then no13-digit sequencescan be formed from only 5 digits.
jfnvjsdkncjfdknvlakdjvbsadoihfcb shfvbcnsHLfc bnshJCbvjhbeshuyvbe b hdfbgehfgbwahucgbvfer fguy gyfuby uyr
125
5040 different 4 digit numbers can be formed with the digits 123456789. This is assuming that no digits are repeated with each combination.
There are 625 of them - too many to list.
27 three digit numbers from the digits 3, 5, 7 including repetitions.
If the two must be different digits, then there 20 possibilities. If they can be the same one, then there are 25 possibilities.
500
24
840