Interchangeable parts

Interchangeable parts are pieces that are made the same way, so that they all fit together the same way. It's like having a pile of Lego pieces: all the pieces are made the same way, so that you can use any piece to build your Lego creation! In the same way, interchangeable parts are pieces that are made the same way, so that they fit together like Lego pieces and can be used for almost any purpose. For example, a car company might use interchangeable parts to make its cars. Instead of needing to make a special part for each car, the company can just use the same interchangeable parts to build each car. This makes production faster and cheaper!