co 8A5=6720 so co 5 chu so khac nhau dk lap tu nhug so tren-ta se co 7A4=840 so co hang don vi la 1
......................840..............................2
...........................................................3
tuong tu voi 4,5,6,7,8
=>840*(1+2+3+4+5+6+7+8+9)=37800.
=>Vay tong cua cac chu so o hang chuc ,tram,nghin cung =37800
=>tong =37800*(10000+1000+100+10+1)=419995800