tính 42 + 9
\(\begin{array}{l}\underline { + \begin{array}{*{20}{c}}{42}\\{\,\,\,9}\end{array}} \\\,\,\,\,\,51\end{array}\) | \(\begin{array}{l}\underline { + \begin{array}{*{20}{c}}{59}\\{\,\,\,9}\end{array}} \\\,\,\,\,68\end{array}\) | \(\begin{array}{l}\underline { + \begin{array}{*{20}{c}}{86}\\{\,\,\,5}\end{array}} \\\,\,\,\,91\end{array}\) | \(\begin{array}{l}\underline { + \begin{array}{*{20}{c}}{38}\\{\,\,\,4}\end{array}} \\\,\,\,\,42\end{array}\) | \(\begin{array}{l}\underline { + \begin{array}{*{20}{c}}{39}\\{\,\,\,4}\end{array}} \\\,\,\,\,43\end{array}\) | \(\begin{array}{l}\underline { + \begin{array}{*{20}{c}}{29}\\{\,\,\,3}\end{array}} \\\,\,\,\,32\end{array}\) | \(\begin{array}{l}\underline { + \begin{array}{*{20}{c}}{89}\\{\,\,\,2}\end{array}} \\\,\,\,\,91\end{array}\) | \(\begin{array}{l}\underline { + \begin{array}{*{20}{c}}{48}\\{\,\,\,3}\end{array}} \\\,\,\,\,51\end{array}\) |