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`bbtext{Bài 1:}`$\\$ \(\begin{array}{l}\begin{array}{*{20}{c}}{ + \begin{array}{*{20}{c}}{5\,9\,7,1\,3\,4\,\,\,\,\,\,\,\,\,\,}\\{\,3\,0\,1,5\,4\,9\,\,\,\,\,\,\,\,\,\,\,}\end{array}}\\\hline{\,\,\,\,\;\;\,\,8\,9\,8,6\,8\,3\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\end{array}\end{array}\) \(\begin{array}{l}\begin{array}{*{20}{c}}{ + \begin{array}{*{20}{c}}{4\,5\,9,1\,2\,7\,\,\,\,\,\,\,\,\,\,}\\{2\,6\,7,9\,8\,0\,\,\,\,\,\,\,\,\,\,\,}\end{array}}\\\hline{\,\,\,\,\;\;\,7\,2\,7,1\,0\,7\,\,\,\,\,\,\,\,\,\,\,\,\,\,\,}\end{array}\end{array}\) $\\$\(\begin{array}{*{20}{c}}{ \times \begin{array}{*{20}{c}}{\,3\,9\,7\,8}\\{\,\,\,\,\,\,\,\,\,\,\,\,2}\end{array}\,\,\,\,\,\,\,\,\,\,\,}\\\hline{\,\,\,\,\,\,7\,9\,5\,6\,\,\,\,\,\,\,\,\,\,\,\,\,}\end{array}\)$\qquad\,\,\,$ \(\left.\begin{array}{l}6\,1\,7,5\,9\,4\\ 2\,7\,7\\\,\,\quad5\,\,5\\\,\quad\,2\,\,1\,9\\\,\qquad1\,5\,4\\\quad\quad\,\,\,\,\,1\,8\end{array}\right|\!\!\!\;\!\!\begin{array}{l}\dfrac{\ \ 3\,4\ \ }{\ \ 1\,8,1\,6\,4\ \ }\\\\\\\end{array}\) $\\$`bbtext{Bài 2:}`$\\$ `3m^2 7dm^2=3xx100dm^2+7dm^2=307 dm^2`$\\$ `7m^2 25cm^2= 7xx10000cm^2+25cm^2=70025cm^2`$\\$`5dm^2 12mm^2=5xx100cm^2+0,12cm^2=500,12cm^2`$\\$ `3dm^2 2cm^2=3xx100cm^2+2cm^2=302cm^2`