What is $346_7 + 165_7 $when expressed in base-$7$?

Question

Hi I used a converter to do this question - and answered the second option. But still unsure, if I made it right.

Answer 1

You can eliminate the other answers by simply considering the units. The units digits are $6$ and $5$. Their sum is $11$, which is congruent to $4$ mod $7$. So the solution must have a $4$ in the units digit.

Answer 2

$$346_7+165_7=(3\cdot7^2+4\cdot7^1+6\cdot7^0)+(1\cdot7^2+6\cdot7^1+5\cdot7^0)=$$ $$=277=5\cdot7^2+4\cdot7^1+4\cdot7^0=544_7$$