Tính
\(\eqalign{ & a)\,\,\left( {{3 \over {16}} - 1,23} \right):\left( {2{1 \over 3} + 1,5} \right) \cr & b)\,\,{4 \over 5} - 2,34:{3 \over {20}} + 5,6..{3 \over 4} \cr} \)
\(\eqalign{ & a)\left( {{3 \over {16}} - 1,23} \right):\left( {2{1 \over 3} + 1,5} \right) = \left( {{3 \over {16}} - {{123} \over {100}}} \right):\left( {{7 \over 3} + {3 \over 2}} \right) \cr & = \left( {{{75} \over {400}} - {{492} \over {400}}} \right):\left( {{{14} \over 6} + {9 \over 6}} \right) = {{ - 417} \over {400}}:{{23} \over 6} = {{ - 417} \over {400}}.{6 \over {23}} = {{ - 1251} \over {4600}} \cr & b){4 \over 5} - 2,34:{3 \over {20}} + 5,6.{3 \over 4} = {4 \over 5} - {{117} \over {50}}.{{20} \over 3} + {{28} \over 5}.{3 \over 4} = {4 \over 5} - {{78} \over 5} + {{21} \over 5} = {{ - 53} \over 5} = - 10{3 \over 5} \cr} \)