8. (10 points) In the equation, $\overline{\mathrm{ABCD}}+\overline{\mathrm{EFG}}=2020$, different letters represent different digits. Therefore, $A+B+C+D+E+F+G=$ $\qquad$ .
【Solution】Solution: $\overline{\mathrm{ABCD}}+\overline{\mathrm{EFG}}=2020$, then:
$$
\begin{array}{r}
\mathrm{ABCD} \\
+\quad \mathrm{EFG} \\
\hline 2020
\end{array}
$$

According to the knowledge of place value, so the units digit $D+G=10$,
since it carries over when it reaches ten, then the units digit of the sum of the tens digits $C+F$ is $2-1=1$, so $C+F=11$, similarly, when it carries over, then the units digit of the sum of the hundreds digits $B+E$ is $10-1=9$, so $B+E=9$, so, $A=2-1=1$,

Therefore, $A+B+C+D+E+F+G=1+9+11+10=31$;
The answer is: 31.