<span><span><span>82</span>=64</span><span><span>82</span>=64</span></span>choices for that.
Now, for the second one, we can't be in the row or column of that first one, so leaving us with <span><span><span>72</span>=49</span><span><span>72</span>=49</span></span> choices.
Then so on, we have <span><span><span>62</span>=36</span><span><span>62</span>=36</span></span> for the third one, <span>2525</span> for the fourth one, and so on <span>……</span>
But, however, we have to remember the rooks are not labeled, thus it doesn't matter specifically about a specific rook's position.
Thus, we have a total of <span><span><span><span>(8!<span>)2</span></span><span>8!</span></span>=40320</span><span><span><span>(8!<span>)2</span></span><span>8!</span></span>=40320</span></span> ways.