According to the query, Baidu Education shows1dm = 0.1m. From this calculation, it can be concluded that 400dm times 0. 1 equals 40 m.
Dm is the calculation unit of length, and dm means decimeter. It can be converted into: 0. 1 decimeter (dm)= 1 cm (cm), 100 mm (mm)= 1 decimeter (dm).