As someone who used to work in retail, if I’m ever caught saying “guess it’s free then,” I sincerely hope everyone in the store immediately stops what they’re doing to form an orderly line to take turns slapping the piss out of me.

Free clue: It’s not 15. That solution doesn’t work for the bottom numbers, and it’s very clearly stated that the 7 is not a typo.

Edit: What makes this puzzle so good is that it tempts you with an “obvious” solution that works with all but the last set, but there’s an equally obvious solution that does fit every set, if you can shake yourself free of the fist one.

The word is fuck. You don’t need to be afraid of the word fuck. It’s just a happy, colorful little word and we should all embrace it.

Say it with me everyone:

fuck