there is a large literature about what Mathematics is. but what about what mathematics is not.
for instance the question displayed in the following image is, for me an example of what mathematics is not(it is quite common to see such kind of question in social media). It is not mathematics because its solution relies on a linguistic joke: 20 for three). Not mathematics lateral thinking, perhaps. Note:Brigadeiro is a candy)
so my question is about references and examples of what mathematics is not.