Question

[Tuấn Anh]

a) 9abc-abc9 =4473

b)abc9+5778=9abc

c) 8abc-abc8 =3618

Answer 1

[Nguyễn Quang Huy]

A)9abc       =4473+abc9

   9000+abc=4473+abcx10+9

   9000       =4482+abcx(10-1)

   9000-4482=abcx9

   4518        =abcx9 => 4518:9=502

b) abcx10+9+5778=9000+abc

    abcx10+5787   =9000+abc

    abcx(10-1)       =9000-5787

    abcx9             =3213 => 3213:9=357

c)8000+abc=3618+abcx10+8

  8000+abc=3626+abcx10

  8000-3626=abcx(10-1)

  4374        =abcx9 => 4374:9=486