10. This is very clear on any standard ruler
There is 1/2.54 inches per centimeter.
centermetre
There are 100 square millimetres in 1 square centimetre.
centermetre stick
There is 0.1 cm in one mm.
25.4 mm in one inch.
2 centermetre
100 mm
one tenth of a milimeter
One inch is exactly 25.4 mm.
There are 1,000 mm in one meter.
One inch is about 25.4 mm