@dave
Bruh... were you thinking about inches? Cause there are 0.9 centimeters in 9mm.
1 cm=10 mm
1 decimeter = 10 cm
1 meter = 10 decimeters
1 decameter = 10 meters
1 hectometer = 10 decameters
1 kilometer = 10 hectometers

It works the same for grams. Literally just replace "meter" for "gram" in all of those.

@dave
Also works for litres.

Lol I know how to use the metric system, I honestly thought you were joking the first time because the questions were so basic.