\(\begin{array}{*{20}{c}}{a)\,\,}\\{}\\{}\end{array}\begin{array}{*{20}{c}}{ + \begin{array}{*{20}{c}}{381}\\{342}\end{array}}\\\hline{\,\,\,723}\end{array}\) \(\begin{array}{*{20}{c}}{b)\,\,}\\{}\\{}\end{array}\begin{array}{*{20}{c}}{ + \begin{array}{*{20}{c}}{550}\\{192}\end{array}}\\\hline{\,\,\,742}\end{array}\)