Incorrect spelling, explanation: the spelling of the cardinal number forty is quite troublesome to both learners and native speakers of English due to the fact that there is the -u letter in four while there is no -u letter in forty. Many users get confused about that and a common mistake is to spell the word forty as fourty, which is wrong.

Correct spelling, explanation: forty is a cardinal number with a long history as its origin can already be tracked in the Germanic language and the word also functioned in Old English. The form close to the contemporary one, however, appeared in Middle English, in which it looked as fourti. There is no -u letter in the word any longer, though, and the correct spelling is forty.

Definition of forty:
1. cardinal number – a number that is between thirty-nine and forty-one;
John is a handsome and intelligent, forty-year-old man.

Phrases with forty:
A few commonly used phrases include:
1. to catch forty winks – to have a short sleep during the day;
Every time I come back home from work I catch forty winks on the train.
2. forty-year-old – refers to a person’s age;
Jane is a successful, forty-year-old businesswoman.