
(1)原式$=\left ( {678+322} \right )^{2}$
$={1000}^{2}$
$=1000000$
(2)原式$={654123}^{2}-\left ( {654123+1} \right )\left ( {654123-1} \right )$
$={654123}^{2}-\left ( {{654123}^{2}-1} \right )$
$={654123}^{2}-{654123}^{2}+1$
$=1$

(1)原式$=\left ( {678+322} \right )^{2}$
$={1000}^{2}$
$=1000000$
(2)原式$={654123}^{2}-\left ( {654123+1} \right )\left ( {654123-1} \right )$
$={654123}^{2}-\left ( {{654123}^{2}-1} \right )$
$={654123}^{2}-{654123}^{2}+1$
$=1$