Solution (source code)

= Solution

Equality of <remainders> after division by eight is a <Euclidean relation>. If $x$, $y$ have the same remainder and $x$, $z$ have the same remainder, then $y$, $z$ have the same remainder. In the notation of <modular arithmetic>,
$$
x\equiv y\pmod8,\quad x\equiv z\pmod8\quad\Longrightarrow\quad y\equiv z\pmod8.
$$
Hence
$$
\boxed{\mathrm{MOD}\ 8\text{ is Euclidean}.}
$$