How much longer is the time for the dance class than the piano class?

Mathematical sentence: \(300\space\text{minit}\space-\space180\space\text{minit}\space=\underline{\quad\quad}\,\text{minit}\)

\(\begin{array} {rr} \small{\color{red}{2}}\, \small{\color{red}{10}}\quad\quad\;\;\;\;\; \\\;\;\cancel{3}\;\cancel{0}\;0\;\text{minutes} \\-\;\;\;1\;8\;0\;\text{minutes} \\\hline\;\;1\;2\;0\;\text{minutes}\\\hline \end{array}\)

So, the dance class is 120 minutes longer than the piano class.