The grammar module quantity-np.grm recognizes special classes of noun phrases that describe quantities.  These involve the quantity nouns "amount", "number", "quantity" and "fraction", used in phrases like "such a large number", "three times that amount", and "much greater a fraction".  They also involve the plural nouns "scores", "dozens", "hundred", "thousand", "millions" (etc.) used in phrases like "many hundreds of thousands".   Such phrases can be used as stand-alone noun phrases, or can be used as modifiers in more general noun phrases, especially as modifiers for the comparatives :"fewer", "less" and "more" in phrases like "his such a great number more cattle" or "a small amount less water".