10 . Ta có \(\overline{120ab}\) = 12000 + \(\overline{ab}\)
Theo đề suy ra: 12000 + \(\overline{ab}\) = 376.\(\overline{ab}\)
Suy ra 12000 = 376.\(\overline{ab}\) - \(\overline{ab}\)
Nên 12000 = 375.\(\overline{ab}\)
Vậy \(\overline{ab}\) = 32
11. \(\overline{206abc}=501.\overline{abc}\)
Suy ra \(206000+\overline{abc}=501.\overline{abc}\)
Nên 206000 = 500.\(\overline{abc}\)
Vậy \(\overline{abc}\) = 412