Find the sum of all the 4-digit numbers which can be formed with the digits 1,2,3,4

find the sum of all the 4 digit numbers that can be formed with the digits 1,2,3,4.

Find the sum of all the four digit numbers which can be formed with the digits 0,1,2 and 3.

Find the sum of all those numbers which can be formed with the digits 0,1,2,3 taken together.

Find the sum of all five digit numbers,that can be formed using the digits 1,2,3,4 and 5 (repetition of digits not allowed)