jmc

We are given $XYD=619+XY$. Examining hundreds digits, we know that $X$ is $6$ or $7$. Examining tens digits, on the right side we cannot have carrying into the hundreds digit, so $X=6$, and thus $Y$ is $7$ or $8$. However, we see that the sum on the right side must have carrying into the tens digit, so $Y=8$. Finally, $D=7$ is trivial. Thus $XYD=\boxed{687}$.