If you do not use a muscle or any part of the body, it tends to become atrophic. So is the case with the brain. The more you use it, the better it becomes.
Shakuntala DeviI have written a book called 'In the Wonderland of Numbers.' It's about a young girl, Neha, who is very poor in mathematics, but in a series of illusory experiences, she becomes a great mathematician.
Shakuntala Devi