Bài 176 trang 67 sgk Toán 6 tập 2, Tính:...

Tính:

a) (1{{13} over {15}}.{left( {0,5} ight)^2}.3 + left( {{8 over {15}} – 1{{19} over {60}}} ight):1{{23} over {24}})

b) ({{left( {{{{{11}^2}} over {200}} + 0,415} ight):0,01} over {{1 over {12}} – 37,25 + 3{1 over 6}}})

Hướng dẫn làm bài:

a) (1{{13} over {15}}.{left( {0,5} ight)^2}.3 + left( {{8 over {15}} – 1{{19} over {60}}} ight):1{{23} over {24}})

( = {{28} over {15}}.{left( {{1 over 2}} ight)^2}.3 + left( {{8 over {15}} – {{79} over {60}}} ight):{{47} over {24}})

( = {{28} over {15}}.{1 over 4}.3 + {{8.4 – 79} over {60}}:{{47} over {24}})

( = {7 over 4} + {{ – 47} over {60}}.{{24} over {47}})

( = {7 over 5} + {{ – 2} over 5})

( = {5 over 5} = 1)

b) ({{left( {{{{{11}^2}} over {200}} + 0,415} ight):0,01} over {{1 over {12}} – 37,25 + 3{1 over 6}}})

( = {{left( {{{121} over {200}} + {{415} over {1000}}} ight):{1 over {100}}} over {{1 over {12}} – {{149} over 4} + {{19} over 6}}})

( = {{left( {{{121} over {200}} + {{83} over {200}}} ight):{1 over {100}}} over {{{1 – 447 + 38} over {12}}}})

( = left( {{{204} over {200}}:{1 over {100}}} ight):{{ – 408} over {12}})

( = {{102} over {100}}.{{100} over 1}.{{ – 12} over {408}})

( = {{ – 12} over 4} =  – 3)