Six in the numerator, six in the denominator, those cancel. All we're left is, on the left-hand side, we're left with 21 plus question mark. All of these other green numbers, those are simplified, five plus two plus two plus four plus eight is 21, and we still have the question mark. We get 21 plus question mark. I'm going to do that green color. 21 plus this question mark. The thing that we're trying to solve for, the missing number, is going to be equal to, is going to be equal to four times six.