Mathematical constants are special numbers that have fixed values and appear frequently in various mathematical contexts. They are important because they help simplify calculations and provide a foundation for many mathematical theories. Some well-known constants include π (pi), which represents the ratio of a circle's circumference to its diameter, and e, the base of natural logarithms, which is essential in calculus and exponential growth. These constants are not just theoretical; they have practical applications in fields such as physics, engineering, and computer science. For example, π is used in calculations involving circles and spheres, while e is crucial in modeling population growth and financial calculations. Understanding these constants is key to grasping more complex mathematical concepts.