An arithmetic logic unit (ALU) is a digital circuit used to perform arithmetic and logic operations. It represents the fundamental building block of the central processing unit (CPU) of a computer. Modern CPUs contain very powerful and complex ALUs. In addition to ALUs, modern CPUs contain a control unit (CU).

The purpose of the ALU is to perform mathematical operations such as addition, subtraction, multiplication and division. Additionally, the ALU processes basic logical operations like AND/OR calculations. It serves as the computational hub of the Central Processing Unit (CPU) for a computer system