Arithmetic is the oldest and most widely used branch of mathematics in the history of the world. In its most basic form, arithmetic encompasses addition, subtraction, multiplication, and division. Arithmetic is used in our everyday lives, from completing simple tasks such as counting to performing complex feats such as computing business models. Because arithmetic is so strongly rooted in our everyday lives, the GMAT absolutely loves to test your knowledge of basic mathematical operations (in tricky ways of course). Therefore, if you want to achieve a good quantitative score, a solid foundation in numbers and the arithmetic operations that govern them is absolutely essential.