There are 10 centimetres in a decimetre, but no centameters in anything!
1 inch is 2.54 centimeters.
1 kilometer=100,000 centimeters
1 centimetre = 10 millimetres.
1 decimetre = 10 centimetres so 9 decimetres = 9*10 = 90 centimetres (not centameters!). Simple!
1 dm
10 cm in 1 dm
none
100
There are about 90 centimeters in a yard because 2.5 cm is about 1 inch
100 mm = 1 dm
1 meter in 10 dm
1 dm = 10 cmSo 5 cm = 0.5 dm