6
use the digit 8 four time to make 89
65
The four in the hundreds place.
28
182
404
6134
9399
1.382 OR 0.000 or 2831
As a digit in other numbers it appears 20 times
Each digit in it has a different place value, so there are four of them in the number.
Process of solvingFrom these four digits '0' cannot be at first place to form four digit numberso we have 1, 2, or 3 can be at thousand's placekeeping one digit at thousand place can have 6 different four digit numberso that means1000*6 + 2000* 6 + 3000* 6 = 36000Now come to hundred's place we can have all four digit at this place , '0' will not contribute any thing to sum so in all four digits number 1,2,3 will be at 4 times on same placeso that means100*4 + 200* 4 + 300 * 4= 2400Now come to tenth's place ...same as hundredso10*4 + 20*4 + 30*4= 240same for unit place1*4 + 2*4 + 3*4= 24in last if you add whole the total sum of all possible four digit number formed is38664