Order of operations clickbait are mathematical puzzles passed around social networking sites like Facebook, where the answer is dependent on getting the right answer to a problem that involves complicated and misleading order of operations questions. The questions involve only basic arithmetic but are extended enough that they can trip people up. They often also include a tagline to flatter/berate the reader, saying that some small percentage of people can answer the question correctly. They use these techniques to draw people in, thus perpetuating through social media, gaining meme status.
Order of operations questions are not that abstract to understand, but they are difficult to execute, especially if someone is say, idly scanning their Facebook feed during a 15 minute break at work. Then people in the comments can hassle each other about what (9-5)*3+4-(12/2) is. And then someone can follow up with a glib comment about how kids are too busy learning self-esteem to learn real skills, and this is why the Chinese have bigger aircraft carriers than us, etc.
These are just another reason why social media is terrible.