1234⋮4123124341321324421313424231142343121432⋮4321
The 24 distinct 4-digit numbers above have been listed out by arranging 1, 2, 3, and 4 in different orders. What is the sum of these 24 numbers?
Hint: You do not need to list out all 24 numbers to find the sum.
From: Derek Niederman's Math Puzzles for the Clever Mind