an expository writing deals with facts and information,it is written to explain something and provide information to the readers.it is informative in nature(ie.passing information from a "know-well" to a "know-less").A good example of an expository essay is the information leaflets published by the HKTB(Hong Kong Tourism Board) promoting different aspects of Hong Kong to tourists.Most writing in textbook is expository. An expository writing may contain a lot of definitions and explanations of words.
An expository writing can do more than simply giving information.You can arrange the facts and information in a way to help you present your discussion,persuasion or arguments.
When doing expository writing, you must not assume that the readers share the same knowledge as you do.As mentioned above, the readers are supposed to know less than the writer in the subject area where the essay focuses on. Therefore, a good piece of expository writing should meet the needs of the readers by gining them the information they went.