How do you find a missing numerator?

Well, honey, if you're missing a numerator, you better start by looking under the couch cushions or in the junk drawer - just kidding! To find a missing numerator in a fraction, you'll need to use some good old-fashioned algebra. Set up an equation with the fraction, solve for the missing numerator by cross multiplying, and voila, you've found that sneaky little number.