To be first is best, but to have a million dollars is better than having one. To be born in the 21st century makes you young; to be born in the 19th century makes you extremely old. Eight twenty-fourths is smaller than two thirds.
To the above twisted logic, add two different ways of writing numbers (words and digits) and several different categories (cardinal, ordinal, fractions and decimals, etc.). English numbers can be a little daunting to those who are just encountering them. However, the rules governing the use of numbers are fairly simple – especially compared to most English grammar rules – and have very few exceptions.
Once you’ve learned your way around the numbers, you just need to remember when it’s acceptable to use digits and when one must use words.