Giải thích các bước giải:
Ta có : $\overline{16abc}\quad\vdots\quad 6,7,8$
$\to \overline{16abc}\quad\vdots\quad 3,7,8$
$\to 16000 +\overline{abc}\quad\vdots\quad 6,7,8$
$\to \overline{abc}$ chia hết cho 8, chia 3 dư 2, chia 7 dư 2
$\to \overline{abc}$ chia hết cho 8, chia 21 dư 2
$\to \overline{abc}=8k, k\in Z$
Mà $\overline{abc}=8k$ chia 21 dư 2
$\to k=21m+16\to \overline{abc}=8(21m+16)=168m+128$
Mà $0\le \overline{abc}\le 999$
$\to 0\le 168m+128\le 999$
$\to 0\le m\le 5$
$\to \overline{abc}\in\{128, 296,464,632,800,968\}$
$\to \overline{16abc}\in\{16128, 16296,16464,16632,16800,16968\}$
