In the past, when some people get a problem wrong, they might have thought that they just don’t have the ability to study math–that they’re not math people. But when you talk to professional mathematicians, the people who are best at math, it turns out that they work a long time on the same problem–and they only spend their time on problems that they struggle with the most. And even though you might think they make up answers on their own, almost always mathematicians have to ask people for help.

–The Carnegie Foundation for The Advancement of Teaching