Short for Arithmetic Logic Unit, the ALU is a complex digital circuit; one of many components within a computer's central processing unit. It performs both bitwise and mathematical operations on binary numbers and is the last component to perform calculations in the processor. The ALU uses to operands and code that tells it which operations to perform for input data. After the information has been processed by the ALU, it is sent to the computer's memory.
Multiple Arithmetic Logic Units can be found in CPUs, GPUs and FPUs. In some computer processors, the ALU is divided into an AU and LU. The AU performs the arithmetic operations, and the LU performs the logical operations.