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.

Females usually reach sexual maturity at about four years of age, males at about ____ years.
six

Most species have four toes, ____ of which are forward-pointing.
three

Scandium is a silvery metal that is soft and has a density of about ____ times that of water.

three