Please solve $(1)$ & $(2)$

Consider a leveling net as the tigure. A and B are two known points, the elevation of A is $50\mathrm{.}00+-0\mathrm{.}00m,$ and the elevation of $B$ is $49\mathrm{.}00+-0\mathrm{.}01m.$ Observation of elevation differences are listed below.

$\backslash$table$[[$Route$,\backslash$table$[[$Elevation$],[$Difference $(m)$