'de' is only placed in for numbers 20 and above... douăzeci de centimetri
Oh! Mulțumesc mult!
Why "nouăsprezece centimetri" and not "nouăsprezece de centimetri"? Mulțumes mult.
what is wrong with "the pencil is nineteen centimeters long"?
That might be, "Creionul are nouăsprezece centimetri lungime".
Mediterran18: It's not at all incorrect. Duo accepted this/my translation as well: "The pencil is nineteen centimeters long". (Aug. 4, 2020).