\(\overline{120ab}:376=\overline{ab}\)
\(\Rightarrow\overline{120ab}:\overline{ab}=376\)
\(\Rightarrow(12000+\overline{ab}):\overline{ab}=376\)
\(\Rightarrow12000:\overline{ab}+\overline{ab}:\overline{ab}=376\)
\(\Rightarrow12000:\overline{ab}+1=376\)
\(\Rightarrow12000:\overline{ab}=376-1\)
\(\Rightarrow12000:\overline{ab}=375\)
\(\Rightarrow\overline{ab}=12000:375\)
\(\Rightarrow\overline{ab}=32\)