In our Compound Numbers category we explain why certain numbers between 21 and 99 have a hyphen when spelled in full. We always start with the grammar rule, and then show you the correct spelling of your particular number. For any particular number not only the cardinal numeral is discussed, but also the ordinal numeral. We then go on to give the answer for thousands, millions and billions which start with the given compound number. Do we have to mention that we also provide examples? Each post also contains a table with numbers close to the number a specific article is about. Every post additionally contains two sections with frequently asked questions and their answers. Last, but not least, we explain how our app can be useful in determining the correct English spelling of any number. In any case, you can always use the designated form if you need further explanations on compound numbers.