1) Viet cac so do sau duoi dang so thap phan co :
Ten don vi la met
57mm , 454dm , 6789cm , 3dm 5cm 7mm
2) Viet so thap phan co :
a. Nam muoi lam don vi , Nam phan muoi , nam phan tram , nam phan nghin
b. Hai nghin khong tram linh hai don vi , tam phan tram
c. Khong don vi , mot phan nghin