The two cerebral hemispheres are separated by the medial longitudinal fissure, a deep groove with a bundle of nerves at the end of it. The cerebral hemispheres are divided into two sections. There is a right and a left section. Both sections contains two types of matter: white and grey.
Popular psychology has given rise to the terms "left brain" and "right brain." People are termed one or the other, based on which hemisphere they use more. The left brain is more logical, and the right brain is more creative. These claims are not necessarily accurate, but there is evidence that certain hemisphere play key roles in functions that translate into everyday life skills and abilities. Language is an area in which both sides of the hemispheres play key roles.
The production of words and grammar is thought to be localized in the left hemisphere of the brain, while intonation and reasoning are localized on the right side of the brain. Numerical computation is thought to be localized in the right hemisphere of the brain. This includes things like fact retrieval and estimation, both approximate and actual estimation. Artistic skills such as drawing and painting come from the left hemisphere, while music makes use of both.