a, \(2.31.12+4.6.42+8.27.3=24.31+24.42+24.27=24.\left(31+42+27\right)=31.100=3100\)
b, \(36.38+36.82+64.69+64.41=36.120+64.110=11360\)
a) \(2.31.12+4.6.42+8.27.3\)
\(=\)\(\left(2.12\right).31+\left(4.6\right).42+\left(8.3\right).27\)
\(=\)\(24.31+24.42+24.27\)
\(=\)\(24.\left(31+42+27\right)\)
\(=\)\(24.100\)
\(=\)\(2400\)
\(36.38+36.82+64.69+64.41\)
\(=\)\(36.\left(38+82\right)+64.\left(69+41\right)\)
\(=\)\(36.120\) \(+64.110\)
\(=\)\(4320\) \(+7040\)
\(=\)\(11360\)
