Compound adjectives and compound nouns with numbers

1. Compound adjectives and compound nouns with numbers.

I am a working mother of a nine-month-old girl.
Our five-year-old often talks obsessively.

Note that in these compounds the word that comes after the number is always singular.

Not:

I am a working mother of a nine-months-old girl.
Our five-years-old often talks obsessively.

Complete the second sentence so that it has a similar meaning to the first sentence.

For example:

My daughter is nine months old.
I have a nine-month-old daughter.