English Numerals - things to remember
  • Cardinal numbers refer to the size of a group.
    I am twenty years old. I have four friends.
  • Ordinal numbers refer to a position in a series.
    My first friend is a student. Today is his nineteenth birthday.
  • Any ordinal name that doesn't end in st, nd, rd (as in "first", "second", or "third"), ends in th.
  • All compound numbers from twenty-one through ninety-nine should be separated by a hyphen (twenty-two, seventy-first).
  • A comma is optional with four-digit numbers but required with five-digit numbers (3000   30,000)

Standard English Language Rules for Numbers: English Numerals Rules for Writing Numbers

Spelling Quizzes Cardinal Numbers Ordinal Numbers