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A= ( 6 - 2/3 + 1/2) -( 5 +5/3 - 3/2) - (3 - 1/3 + 5/2)
= 6 - 2/3 + 1/2 - 5 - 5/3 + 3/2 - 3 + 1/3 - 5/2
= (6-5-3) - (2/3 + 5/2 - 1/3) + (1/2 +3/2 -5/2)
= -2 - 2 + (-1/2)
= -4 -1/2
=-9/2
A = ( 6 - 1 ) - ( 5 + 1 / 6 ) - ( 3 + 13 / 6 )
A = 5 - 31 / 6 - 31 / 6
A = -16 / 3
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Ta có: \(A=\dfrac{1-0.5\cdot\left(3.84-2.4\right):0.8}{\dfrac{4}{5}-\left(1\dfrac{1}{3}-2\dfrac{1}{6}\right)-1.5}\)
\(=\dfrac{1-0.5\cdot1.44:0.8}{\dfrac{4}{5}-\left(\dfrac{4}{3}-\dfrac{13}{6}\right)-\dfrac{3}{2}}\)
\(=\dfrac{1-0.9}{\dfrac{4}{5}+\dfrac{5}{6}-\dfrac{3}{2}}=\dfrac{0.1}{\dfrac{2}{15}}=\dfrac{3}{4}\)
Giải:
A=1-0,5.(3,84-2,4):0,8 / 4/5-(1 1/3 - 2 1/6)-1,5
A=1-0,5.1,44:0.8 / 4/5-(4/3-13/6)-3/2
A=1-0.9 / 4/5-(-5/6)-3/2
A=0.1 / 2/15
A= 1/10 : 2/15
A=3/4
Chúc bạn học tốt!
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c)
\(\left(1-\frac{1}{2}\right)+\left(1-\frac{1}{6}\right)+....+\left(1-\frac{1}{42}\right)+\left(1-\frac{1}{56}\right)\)
\(\left(1+1+1+....+1+1\right)+\left(\frac{1}{1\times2}+\frac{1}{2\times3}+...+\frac{1}{6\times7}+\frac{1}{7\times8}\right)\)(Có 7 số 1)
\(7+1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+....+\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}\)
\(7+1-\frac{1}{8}=\frac{63}{8}\)
Gợi ý 1 bài c) còn d) e) cũng làm như vậy nhé
Chúc bạn học tốt !!!
\(\left(\dfrac{6}{5}-2,4\right):\dfrac{-3}{5}-\dfrac{3}{2}.\left(1\dfrac{1}{2}:\dfrac{1}{2}\right)\)
= \(\dfrac{-6}{5}\): \(\dfrac{-3}{5}-\dfrac{3}{2}.\left(\dfrac{3}{2}:\dfrac{1}{2}\right)\)
= \(\dfrac{-5}{2}\)
\(\left(\dfrac{6}{5}-2,4\right):\left(-3,5\right)-\dfrac{3}{2}.\left(1\dfrac{1}{2}:\dfrac{1}{2}\right)=-\dfrac{6}{5}:\left(-\dfrac{7}{2}\right)-\dfrac{3}{2}.3=\dfrac{12}{35}-3=-\dfrac{93}{35}\)