Ta có : A = abcdeg - (abc+deg)
= abc.1000 + deg - abc - deg
= abc.999
= abc.27.37
=> A chia hết cho 37
Vì abc + deg chia hết cho 37 mà A chia hết cho 37 nên abcdeg chia hết cho 37
\(\overline{abc}+\overline{deg}⋮37\)
\(\overline{abcdeg}=1000\cdot\overline{abc}+deg\)
\(\Rightarrow999\cdot\overline{abc}+\overline{abc}+\overline{deg}\)
\(\Rightarrow\left(\overline{abc}\cdot27\cdot37\right)+\overline{abc}+\overline{deg}\)
Do \(\overline{abc\cdot37\cdot27⋮37}\)nên \(\overline{abcdeg}⋮37\)
/abcdeg = 1000./abc + /deg
/abcdeg = 999./abc + /abc + /def
/abcdeg = 37.27./abc + /abc + /deg (*)
(*) ta có:
/abc + /deg chia hết cho 37 => VP chia hết cho 37 => VT = /abcdeg chia hết 37
37 chuan 100000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000%
Ta có:
A= abcdeg - ( abc+deg)
= abc.1000 + deg - abc - beg
= abc.999
= abc.27.37
=> A chia hết cho 37
Vì :
abc + deg chia hết cho 37 mà A chia hết cho 37 nên abcdeg chia hết cho 37