The four numbers 2.3.4.5 can be used to form many four digit numbers without repetition. What is the sum of all these four digit numbers? Decimals

The four numbers 2.3.4.5 can be used to form many four digit numbers without repetition. What is the sum of all these four digit numbers? Decimals

If the numbers 2, 3, 4 and 5 are composed of four digits without repetition, the number is the total arrangement of four different elements = 4 * 3 * 2 * 1 = 24 kinds
These numbers are arranged in vertical form, from the individual to the thousand. On each digit, four numbers appear six times respectively
So the sum of each digit = (2 + 3 + 4 + 5) * 6 = 84
So the sum of all these four digits
= 84 * 1000 + 84*100 + 84*10 +84
= 84 * 1111
= 93324

With the four numbers of 5, 6, 7 and 8, many four digit numbers without repetition can be formed. The sum of all these four digit numbers is______ ．

(5 + 6 + 7 + 8) × 6666, = 26 × 6666, = 13 × 6666 × 2, = 86658 × 2, = 173316

With the four numbers of 0, 1, 2 and 3, many four digit numbers without repetition can be formed. What is the average of all these four digit numbers?
As above

0,1,2,3 these four numbers can be composed of many four digits without repetition: 3 * 3 * 2 * 1 = 18 analysis: thousand digits can be 3,2,1, respectively, six 3,6 2,6 1, thousand digits sum is: (6 * 3 + 6 * 2 + 6 * 1) * 1000 = 36000, hundred digits can be 3,2,1,0, of which 3,2,1 appear four times, 0 appears six