Microsoft and open source

Microsoft is a company that makes lots of products such as computers, computer programs, and games. Microsoft's products are usually closed source, which means that the inner workings of them are kept private and only people inside the company and trusted customers know how they work. Open source is a different kind of product, where anyone can look at the source code (the instructions inside the product) to see and understand how it works, and can even make changes to it to improve it in any way they would like. Open source products are often free to use and develop, so more people can work together on them. Microsoft has started to work with open source more in the last few years, so that customers and developers can all work together more easily to build great products.