You have mu, you have n over n. Those cancel out. So you have plus mu squared. So that was a very nice simplification. And then this simplifies to, can't do much on this side, so the sum from i is equal to 1 to n of x sub i squared over n. And then see, we have minus 2 mu squared plus mu squared. Well, that's the same thing as minus mu squared. Minus the mean squared. So this, already, we've kind of come up with a neat way of writing the variance.