1. Calculate:
$$
\left(\frac{404445^{2}}{202222 \times 202223 \times 202224}-\frac{202223}{202222 \times 202224}-\frac{202222}{202223 \times 202224}\right) \times 12639=
$$
$\qquad$
【Answer】 $\frac{1}{8}$
【Solution】
$$
\begin{array}{l}
=\frac{404445^{2}-202223^{2}-20222^{2}}{202222 \times 202223 \times 202224} \times 12639 \\
=\frac{20222 \times 606668-20222^{2}}{202222 \times 202223 \times 202224} \times 12639 \\
=\frac{20222 \times 404446}{202222 \times 202223 \times 202224} \times 12639 \\
=\frac{12639}{101112} \\
=\frac{1}{8}
\end{array}
$$