And this is important to our derivation of the Poisson distribution. But just to make this in real numbers, if I had 7 factorial over 7 minus 2 factorial, that's equal to 7 times 6 times 5 times 4 times 3 times 2 times 1 over 2 times, no sorry, 7 minus 2, this is 5. So it's over 5 times 4 times 3 times 2 times 1. These cancel out, and you just have 7 times 6. And so it's 7, and then the last term is 7 minus 2 plus 1, which is 6. 7 minus 2 plus 1. And you had, in this example, k was 2, and you had exactly 2 terms.