tính 91 – 84

\(\begin{array}{l}\underline { - \begin{array}{*{20}{c}}{91}\\{84}\end{array}} \\\,\,\,\,\,\,\,7\end{array}\)

\(\begin{array}{l}\underline { + \begin{array}{*{20}{c}}{63}\\{28}\end{array}} \\\,\,\,\,91\end{array}\)

\(\begin{array}{l}\underline { - \begin{array}{*{20}{c}}{82}\\{34}\end{array}} \\\,\,\,\,48\end{array}\)

\(\begin{array}{l}\underline { + \begin{array}{*{20}{c}}{66}\\{27}\end{array}} \\\,\,\,\,93\end{array}\)