tính 990 - 126

\(\begin{array}{l}\underline { - \begin{array}{*{20}{c}}{990}\\{126}\end{array}} \\\,\,\,\,864\end{array}\)

\(\begin{array}{l}\underline { + \begin{array}{*{20}{c}}{725}\\{135}\end{array}} \\\,\,\,\,860\end{array}\)

\(\begin{array}{l}\underline { - \begin{array}{*{20}{c}}{393}\\{127}\end{array}} \\\,\,\,\,266\end{array}\)

\(\begin{array}{l}\underline { + \begin{array}{*{20}{c}}{125}\\{625}\end{array}} \\\,\,\,\,750\end{array}\)