Toán Lớp 7: bài 1 :
a) 6/7 – ( 2/11 +6/7)
b) ( 1 1/2 – 0,5) : (-3) mũ 2 + 1 /3 – 1/6
c) -(-5/8) – (-9 / 22 + 5/8)
d) – 1,53 : ( 5 5/28 – 1 8/9.1,25 + 1 16/63)
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Toán Lớp 7: bài 1 :
a) 6/7 – ( 2/11 +6/7)
b) ( 1 1/2 – 0,5) : (-3) mũ 2 + 1 /3 – 1/6
c) -(-5/8) – (-9 / 22 + 5/8)
d) – 1,53 : ( 5 5/28 – 1 8/9.1,25 + 1 16/63)
giúp mik với
Comments ( 1 )
a)\dfrac{6}{7} – \left( {\dfrac{2}{{11}} + \dfrac{6}{7}} \right)\\
= \dfrac{6}{7} – \dfrac{2}{{11}} – \dfrac{6}{7}\\
= \left( {\dfrac{6}{7} – \dfrac{6}{7}} \right) – \dfrac{2}{{11}}\\
= – \dfrac{2}{{11}}\\
b)\left( {1\dfrac{1}{2} – 0,5} \right):{\left( { – 3} \right)^2} + \dfrac{1}{3} – \dfrac{1}{6}\\
= \left( {1 + \dfrac{1}{2} – \dfrac{1}{2}} \right):9 + \dfrac{1}{6}\\
= 1:9 + \dfrac{1}{6}\\
= \dfrac{1}{9} + \dfrac{1}{6}\\
= \dfrac{5}{{18}}\\
c) – \left( { – \dfrac{5}{8}} \right):\left( {5\dfrac{5}{{28}} – 1\dfrac{8}{9}.1,25 + 1\dfrac{{16}}{{63}}} \right)\\
= \dfrac{5}{8}:\left( {5 + \dfrac{5}{{28}} – \dfrac{{17}}{9}.\dfrac{5}{4} + \dfrac{{79}}{{63}}} \right)\\
= \dfrac{5}{8}:\dfrac{{57}}{{14}}\\
= \dfrac{5}{8}.\dfrac{{14}}{{57}}\\
= \dfrac{{35}}{{228}}
\end{array}$