Given a sentence, fill out the missing word with a 'no' or a number (between zero and ten). You should write the numbers with english alphabet, like: four instead of 4.

[EX Q]: All orthodontists are dentists, but only about ____ percent of dentists are orthodontists.
[EX A]: six

[EX Q]: International mail consists of ____ categories of mail.
[EX A]: three

[EX Q]: Most girls begin to wear their first coils, weighing as much as ____ kg, at age five.
[EX A]:
three