Decomposition in computing refers to the process of breaking down a complex problem or system into smaller, more manageable parts that are easier to conceive, understand, program, and maintain). There are different types of decomposition defined in computer science, including algorithmic decomposition, structured analysis, and object-oriented decomposition). Algorithmic decomposition breaks a process down into well-defined steps, while structured analysis breaks down a software system from the system context level to system functions and data entities. Object-oriented decomposition breaks a large system down into progressively smaller classes or objects that are responsible for some part of the problem domain).

Decomposition is also an important concept in computational thinking, which is the process of breaking down complex problems into smaller, more manageable parts. This helps to identify patterns, eliminate extraneous details, and solve the problem step by step instead of trying to do so all at once. Decomposition is a powerful tool that guides how we approach everyday projects and tasks, and it is employed in student learning across different subjects such as English Language Arts and Mathematics.

In computer programming, decomposition can come into play when students are programming a new game, for example, by identifying the elements or parts of a complex problem and dividing a task into various subtasks. In C programming, the unit of decomposition is the function and the ADT, while in C++, the unit of decomposition is the class. The goal of decomposition is to divide the problem into independent sub-problems, and black boxes are the natural extension of this goal.