When do you put a hyphen between numbers?

If I chose twenty three carrots at the green grocers is that okay?

Is my daughter twenty three years old or twenty-three years old?

Do I live at number sixty four or sixty-four?

I should know this, but my mind has gone blank!

I wouldn't put hyphens anywhere in your examples, Kat.

They should all be hyphenated. I've just checked, and Hart's Rules agrees.

Emma

Thanks Jem, so whe do we hyphenate numbers?

Sorry, stupid question but my mind's gone blank today - too much playing the Wii with my niece who's staying over!

Kat x

<Added>

When

Better not ask me, then, Kat. I've gone through life never hyphenating numbers. Do we say one-hundred-and-four then?

Ooh Emma thanks for that - okay here's another question when do we NOT hyphenate numbers then?

Kat x

It depends on house style, but generally numbers over 100 are written in figures, unless they're really round (a hundred, two thousand). So the question doesn't arise.

Emma

I agree, Emma, that I would hyphenate all of Katerina's original examples. However, I was going to say that it's because two words are representing one number. But this doesn't hold true with 'two thousand', which I would not hyphenate, and which is still representing one number.

As you say, in the end it's a matter of house style, and not worth fretting about.

Deb