How to do a magic trick

Do you believe in magic? People often amazed at the tricks that made by the magicians and are also wondering how that happens. Let me show you a simple magic trick in math. First, tell your friends to write a number between 1 and 10. Remember to remind them not show you the number. Then, tell your friends to multiply the number by 9. Third, tell him/her to add the two digits in the number. For example, if the number is 18, add 1 and 8 to get 9. Here's the trick: Whatever you choose any number, in the end, you will get 9! This is a great trick to use anywhere to get your friends excited about math. Just try it!