year old

Newguest, if you use hyphen(21 year-old), year doesn't take the -s, without a hyphen it should be with -s.

So, the correct answer is '21 year-old'?

Why cannot use '21 years old'?

I don't understand...[:^)]

Spectacle, look here:
I am 5 years old
I am a 5 year-old girl.

Is that clear?

In your example I'd say 21 years old.

Hi Paulio,

Yes, that's very clear!

Thanks so much!

PaulioSpectacle, look here: I am 5 years old I am a 5 year-old girl. Is that clear? In your example I'd say 21 years old.

I am a 5-year-old girl. (Another hypen is required.)

PaulioSpectacle, look here: I am 5 years old I am a 5 year-old girl. Is that clear? In your example I'd say 21 years old.

John is the only 6-foot (an adjective) 10 year old ( a noun) in the class.

Hyphen is not always used except in abov

Hi Goodman

Can I safely assume you would consider the following sentence to be correct?

The all-star team is made up mainly of twelve-year-olds.

Goodman, hyphen is required as YL has noted. I've made a typo...

thanks for all replies

So when we speak, we say 21 years old or 20 year old?