Tích 5 stn đầu tiên khác 0 là 120
Tổng 10 stn đầu tiên là 45
Tổng là :
120 + 45 = 165
165 là đúng 100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000% đấy