Ta có: \(\overline{abc}+\overline{deg}⋮37\)
\(\Leftrightarrow1000.\left(\overline{abc}+\overline{deg}\right)⋮37\)
\(\Leftrightarrow1000\overline{abc}+1000\overline{deg}⋮37\)
\(\Leftrightarrow\overline{abc000}+\overline{deg}+999\overline{deg}⋮37\)
\(\Leftrightarrow\overline{abcdeg}+999\overline{deg}⋮37\)
mà \(999\overline{deg}⋮37\)\(\Rightarrow\)\(\overline{abcdeg}⋮37\)( ĐPCM )
ta có abcdefg =abc*1000+deg =abc*999 +abc +deg mà abc*999 chia ht cho 37
=>abc +deg chia ht cho 37
