The central processing unit, or CPU, is often referred to as the brain of a computer. It is responsible for executing instructions from programs and performing calculations. The CPU processes data by following a set of instructions, which allows it to carry out tasks such as running applications, managing hardware, and performing calculations. CPUs are made up of several components, including the arithmetic logic unit (ALU), which performs mathematical operations, and the control unit, which directs the flow of data within the CPU. Modern CPUs can have multiple cores, allowing them to handle several tasks simultaneously, improving overall performance and efficiency.