Ta có:
\(\overline{abc3}=\overline{abc}\times10+3\)
\(\overline{6abc}=6000+\overline{abc}\)
Phép tính trở thành:
\(\overline{abc}\times10+3+4125=6000+\overline{abc}\)
\(\overline{abc}\times10+4128=600+\overline{abc}\)
\(\overline{abc}\times10-\overline{abc}=6000-4128\)
\(\overline{abc}\times\left(10-1\right)=1872\)
\(\overline{abc}\times9=1872\)
\(\overline{abc}=1872:9=208\)
Vậy: \(a=2,b=0,c=8\)