Use of significant figures in addition and subtraction
No. The answer isn't accurate enough. Say, for example I wish to add two numbers: $1.23$ and $2.367$.

I proceed like this, but I've no idea what the third digit after the decimal in $1.23$  is and so I represent it as $?$.

$$\begin{align*} 1 &amp;.23? \\ + 2 &amp;.367 \\ \hline 3 &amp;.59? \\ \hline  \end{align*}$$

This is why the end result is rounded off with the number of digits equal to the number having the fewest number of digits you initially set off with.