\(220,33-\overline{ab,cd}=\overline{abc,d}\)
Ta có:
\(220,33-\overline{ab,cd}=\overline{ab,cd}.10\)
\(220,33=\overline{ab,cd}+10.\overline{ab,cd}\)
\(220,33=\overline{ab,cd}.\left(10+1\right)\)
\(220,33=\overline{ab,cd}.11\)
\(\overline{ab,cd}=\frac{220,33}{11}\)
\(\overline{ab,cd}=20,03\)
\(\rightarrow\overline{abcd}=2003\)