smc

If we change $0$, the units column would be incorrect. If we change $1$, then the leading $1$ in the sum would be incorrect. However, looking at the $2$ in the hundred-thousands column, it would be possible to change the $2$ to either a $5$ (no carry) or a $6$ (carry) to create a correct statement. Changing the $2$ to a $5$ would give $745586+859430$ on top, which equals $1605016$. This does not match up to the bottom. Changing the $2$ to a $6$ gives $746586+869430$ on top, which has a sum of $1616016$. This is the number on the bottom if the $2$s were changed to $6$s. Thus $d=2$ and $e=6$. so $d+e=8\boxed{8}$