For the record, I was not suggesting that YOU are one of the parents that think your DD is the best when she's not. Sorry if it sounded like I implied that.
Are all the competitions individual or are their "team" competitions as well? If the latter, I will say that in life, you often find yourself in situations where you already know what to do, but because the outcome depends on everyone getting it, you have to wait for them. While you are frustrated, you also have to count on the other people understanding it too. ya know?
And totally playing devil's advocate here... How would you feel if your DD was the one not getting it, and the teacher was just skipping ahead after she showed everyone once or twice?
I hope that doesn't sound like I'm attacking you, because I am not at all (and for the record, if I was in your shoes, it would frustrate me as well!!!). I think that you need to talk with the teacher and also search out your other options if there are any.
Would your DD like to help the class learn? Maybe the teacher would let her work with a group of girls that don't understand it or something?