Difference between quantitative adjective and number adjective

Dear Student, 

Number adjective: They give the exact number amount of a noun. They use numbers to qualify a noun. 

Eg: He has three bikes. ('Three' is a number adjective)

Quantitative adjective: They indicate the approximate ( in few cases - even the exact quantity) quantity of a noun. However, they do not use numbers to qualify a noun. 

Eg: 1. He has no friends. ( 'No' is a quantitative adjective. It denotes the exact number of friends that he has. He has no friends means he has zero friends. Note that 'no' is not a number so it is not a number adjective.)
2. He has many books. ( 'Many' is a quantitative adjective. It denotes the approximate number of books that he has.)

Regards,