Answer:
20 cause when According to Sciencealert, the longest math equation contains around 200 terabytes of text. Called the Boolean Pythagorean Triples problem, it was first proposed by California-based mathematician Ronald Graham, back in the 1980s.The Navier-Stokes equation, for me is the hardest of all. This is the full Navier-Stokes equation in conservative form. It looks pretty simple, but as one will dig in, they will notice why it is the hardest one.