You might think that the difference in spelling forty and fourty is an American and British English variation such as in color and colour. But the correct spelling is forty in both. Learn the history and rules of spelling 40 as forty, not fourty, and how to use it in sentences. Find out why you need to hyphenate compound numbers after forty and see examples of forty usage. Number Names 1 to 40 - How to write numbers 1 to 40 in words? Learn to spell numbers from 1 to 40 with Solved Examples, FAQs, 1 to 40 Spelling Charts, and more.