Calculate the Determinant? $$D=\begin{bmatrix}
246 & 427 & 327 \\
1014 & 543 & 443 \\
-342 & 721 & 621 \\
\end{bmatrix}$$
What's the trick?
Hints?
Of course I know calculate by definition...
Please don't do that by cheating.

To simplify the calculation, you can start by subtracting column three from column 2. That will not change the value of the determinant, but will simplify its calculation. Then subtract the first row from the other two, and you can then, essentially, compute the value of the determinant of a $2\times 2$ matrix by expansion of the minor using the appropriate column.
In problems like this (particularly when looking to simplify the calculation of determinants of even larger matrices, we can use elementary row/column operations can  to simplify the calculation of the determinant, but recall if and how each operation impacts the value of the original determinant.
