Actually the opposite is true. Use of Marijuana tends to reduce your IQ, and your ability to solve mathematical problems.
However use of Marijuana will help you with your Sociology Professors in College, especially if you are willing to share some of your Marijuana with them.
No, you will not become more intelligent because you smoke marijuana. I've, in my high school days, found that it was easier for me to concentrate after a bowl, and that made it easier for me to learn, I suppose. But that's not directly because of marijuana, it's an indirect relationship.