How do you write two hundred sixteen ten-thousandths in standard notation?

The number "one hundred one" thousandths is 0.101

The distinction must be made between "one hundred one" thousandths and "one hundred" one-thousandths (which is why it is seldom used, and needs a hyphen if is used). In any event 100/1000 is not in simplest form, but might be used in some rare cases.