a) 41 826 + 26 418

\(\begin{array}{l}\underline { + \begin{array}{*{20}{c}}{41\,\,826}\\{26\,418}\end{array}\,\,} \,\,\\\,\,\,\,\,68\,244\end{array}\)

b) 17 670 - 3 965

\(\begin{array}{l}\underline { - \begin{array}{*{20}{c}}{17\,\,670}\\{\,\,3\,\,965}\end{array}\,\,} \,\,\\\,\,\,\,13\,\,705\end{array}\)

c) 10 289 x 7

\(\begin{array}{l}\underline { \times \begin{array}{*{20}{c}}{10\,\,289}\\{\,\,\,\,\,\,\,\,\,\,\,\,\,7}\end{array}} \\\,\,\,72\,\,023\end{array}\)

d) 68 965 : 5

\[\begin{array}{l}\left. {\underline {\begin{array}{*{20}{c}}{68\,\,965}\\{5\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\end{array}} } \right|\,\begin{array}{*{20}{c}}{\underline {\,\,\,\,\,\,5\,\,\,\,\,\,\,} }\\{13\,\,793}\end{array}\\\underline {\begin{array}{*{20}{c}}{18\,\,\,\,\,\,}\\{15\,\,\,\,\,\,}\end{array}\,\,\,} \\\underline {\begin{array}{*{20}{c}}{\,\,\,39}\\{\,\,\,\,35\,\,}\end{array}} \,\,\,\\\,\,\,\,\,\,\underline {\,\begin{array}{*{20}{c}}{46}\\{45}\end{array}\,} \\\,\,\,\,\,\,\,\underline {\,\,\,\,\begin{array}{*{20}{c}}{15}\\{15}\end{array}\,\,} \\\,\,\,\,\,\,\,\,\,\,\,\,\,\,0\end{array}\]

Một hình vuông có chu vi là 36 cm thì cạnh của hình vuông có độ dài là: