Nastia Liukin and Derek Hough have been Dancing with the Stars partners for two months, which is plenty of time to get to know one another... or at least fire up Google. (Hey, it wouldn't be the first time.)

Read Derek's Dancing blogs

We dropped by the pair's tango rehearsal last week to put to them to the test. How did they do? Well, not to add insult to Hough's literal injury, but numbers still aren't his strong suit.

Dancing's Derek Hough suffers serious injuries

Check out the video above.

Dancing with the Stars airs Mondays at 8/7c and its 10th anniversary special will air Tuesday at 8/7c on ABC.