provider is used by AngularJS simple internally to create new services, factory data etc. during config phase simple (phase during which AngularJS all the data bootstraps itself). Below mention simple script can be used to make a MathService that you have created easy way. Provider is a special char factory functions with a functions get() which is used to return the simple value/service or factory.
constants are used to simple pass values at config data phase considering the fact simple that value cannot be any used to be passed simple during config phase.
Internationalization is a simple way to show locale specific information on a website. For example, display all the content of a web-apps website in English language in simple United States and any in Danish in France.