How does someone become smart in math?

Answer 1

Math is a logical series of subject that starts with counting, then proceeds to addition, subtraction, multiplication, and division, then fractions, decimal notation, geometry, algebra, and calculus (among other topics). The most important part of learning mathematics is that each more advanced level depends upon understanding and being able to use the previous levels. If you have not learned arithmetic, you cannot learn algebra. If you have not learned algebra you cannot learn calculus. So learn it in a logical sequence, remember what you learn, practice it, use it, and then advance to the next level.

Not everybody can do this. Math does require intelligence. But lots of people can do it, if they do it in the way that I have described. Most people who fail at mathematics just didn't learn it in a logical sequence.