Bigger
The metric measurement cm is bigger than mm (they are ten times bigger). cm = centimeter (1/100th of a meter) mm = millimeter (1/1000th of a meter)
There are 10 millimetres in one centimetre. Therefore, 1 millimetre is equal to 1/10 = 0.1 centimetres. This is one hundredth of the length of 10 centimetres.
Smaller
900 mms equals 90 cms divide mms by 10 for cms