tính 90 – 35

\(\begin{array}{l}\underline { - \begin{array}{*{20}{c}}{90}\\{35}\end{array}} \\\,\,\,\,55\end{array}\)

\(\begin{array}{l}\underline { + \begin{array}{*{20}{c}}{59}\\{21}\end{array}} \\\,\,\,\,80\end{array}\)

\(\begin{array}{l}\underline { - \begin{array}{*{20}{c}}{52}\\{17}\end{array}} \\\,\,\,\,35\end{array}\)

\(\begin{array}{l}\underline { + \begin{array}{*{20}{c}}{37}\\{24}\end{array}} \\\,\,\,\,61\end{array}\)