Approximation means that one thing is similar to another thing, but not exactly the same. It can be used in many properties to refer to situations where things are almost the same but not exactly the same.

Approximations are most often used with numbers, but are also common with mathematical functions, shapes, and the laws of physics.

In science, physical phenomena are converted into models with similar structures. When accurate models are difficult to apply, relatively simple models are used to simplify intermediate calculations. When specific things cannot be stated accurately, they are handled in an approximate way.

The type of approximation will depend on the information available, the level of accuracy required, and the time and effort that can be saved.