Here is an example of an activity that would promote noticing of number phrases used in singular form before a noun (see Question 1).
Bring into class some advertisements from the real estate section of the newspaper. Such advertisements contain phrases such as ‘3-bedroom house’, ‘two-car garage’, ‘twobathroom apartment’, ‘5-acre lot’, etc. See how many of these number phrases before nouns students can find. They may need help with any abbreviations that are used.