[tex]\displaystyle \\
\overline{abc}-\overline{ab}-\overline{c}=486 \\ \\
100a+10b+c -(10a+b) -c = 486 \\ \\
100a+10b+c -10a-b -c = 486 \\ \\
90a +9b = 486 \\ \\
9(10a+b)=486 \\ \\
9\times \overline{ab} = 486 \\ \\
\overline{ab} = \frac{486}{9} = 54 \\ \\ \\
\Longrightarrow~~\boxed{a=5;~~b=4~~\text{si } ~c \in \{0;~1;~2;~3;~4;~5;~6;~7;~8;~9\} }\\ \\
\Longrightarrow~~\boxed{\overline{abc} \in \{540;~541;~542;~543;~544;~545;~546;~547;~548;~549\}}[/tex]