Đề bài
Thực hiện các phép tính :
\[\eqalign{ & a]\;39.13 + 87.39 \cr & b]\;15.42 - 18.32 + 3.42 \cr & c]\;125.98 - 125.46 - 52.25 \cr & d]\;80 - \left[ {130 - {{\left[ {12 - 4} \right]}^2}} \right] \cr & e]\;135 - \left[ {1300 - {{\left[ {{4^2} - 2.3} \right]}^3}} \right]:60 \cr & g]\;50:\left\{ {2.\left[ {52 - {{\left[ {3.5 - {2^3}.3} \right]}^3}} \right]} \right\} \cr & h]\;{7^{81}}:{7^{79}} + {5.5^2} - {2^3}.3 \cr & i]\;{2.2^3} + {2^0}{.3^5} - 11. \cr} \]
Lời giải chi tiết
\[\eqalign{ & a]\;39.13 + 87.39 = 39[13 + 87] \cr&= 39.100 = 3900 \cr & b]\;15.42 - 18.32 + 3.42 \cr&= 42.[15 + 3] - 18.32 \cr & = 42.18 - 18.32 = 18.[42 - 32]\cr& = 18.10 = 180 \cr & c]\;125.98 - 125.46 - 52.25 \cr&= 125.[98 - 46] - 52.25 \cr & = 125.52 - 52.25 \cr&= 52.[125 - 25] = 52.100 = 5200 \cr & d]\;80 - \left[ {130 - {{\left[ {12 - 4} \right]}^2}} \right]\cr& = 80 - [130 - {8^2}] \cr&= 80 - [130 - 64] = 80 - 66 = 14 \cr & e]\;135 - \left[ {1300 - {{[{4^2} - 2.3]}^3}} \right]:60 \cr & = 135 - {\rm{[}}1300 - {[16 - 6]^3}{\rm{]}}:60 \cr&= 135 - [1300 - {10^3}]:60 \cr & = 135 - [1300 - 1000]:60 \cr&= 135 - 300:60 = 135 - 5 = 130 \cr & g]\;50:\left\{ {2.\left[ {52 - {{\left[ {3.5 - {2^3}.3} \right]}^3}} \right]} \right\} \cr & = 50:{\rm{\{ }}2.{\rm{[}}52 - {[15 - 12]^3}{\rm{]\} }}\cr& = 50:{\rm{[}}2.[52 - {3^3}]{\rm{]}} \cr & = 50:{\rm{[}}2.[52 - 27]{\rm{]}} \cr&= 50:[2.25] = 50:50 = 1 \cr & h]\;{7^{81}}:{7^{79}} + {5.5^2} - {2^3}.3 \cr&= {7^{81 - 79}} + {5^{1 + 2}} - {2^3}.3 \cr & = {7^2} + {5^3} - 8.3 \cr&= 49 + 125 - 24 = 174 - 24 = 150 \cr & i]\;{2.2^3} + {2^0}{.3^5} - 11\cr& = {2^{1 + 3}} + {1.3^5} - 11 \cr & = {2^4} + {3^5} - 11 \cr&= 16 + 243 - 11 = 259 - 11 = 248 \cr} \]