Tìm 0 trong mỗi hình dưới đây:
999999999999999999999999999999909999999999999999999999
999999999999999999999999999999999999999999999999999999999999999999999999999999999999990999999999999999999999999999
999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999909999999999999999999999999999999999999999999999999099999999999999999999999999999999999999999999999999999999999999999
Có 4 chữ số 0 : Hàng 1 có 1 chữ số 0 .Hàng thứ 2 có 1. Hàng thứ 4 có 2 chữ số 0
Chữ số 0 ở dòng thứ hai , bn nhé !