What do you do when you want to refer to a number that you do not know? Suppose you wanted to refer to the number of shops in your town, but haven't counted them yet. You could say 'blank' number of shops, or perhaps '?' number of shops.
In mathematics, a letter is often used to represent a number that you do not know - so you could say 'x' number of shops, or 'q' number of shops. In this Revision Bite we shall be taking a closer look at using letters to represent numbers.
