Question

a.2/15+(-5/24)

b.(-5/9)-(-7/27)

c.(-7/12)+0,75

d.0,34+(-5/17)

2. Nhân số hữu tỉ

a.2/5.(-1,25) 

b.(-3/5).(-7/15)

 

 

Answer 1

`2/15+(-5/24) = 2/15 - 5/24 = 16/120 - 25/120 =(16-25)/120 = (-9)/120 =(-3)/30`

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`(-5)/9 - (-7/27) = (-5)/9 + 7/27 = (-15)/27 + 7/27 = (-15 +7)/27 = (-8)/27`

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`(-7)/12 + 0,75 = (-7)/12 + 3/4 = (-7)/12 + 9/12 = (-7+9)/12 = 2/12 = 1/6`

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`0,34 + (-5/17) = 17/50 - 5/17 = 289/850 - 250/850 = (289 - 250)/850 = 39/850`

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`2/5 . (-1,25) = 2/5 . (-5/4) = (2.(-5))/(5xx4) = (-10)/20 = (-1/2)`

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`(-3/5) . (-7)/15 = (-3.(-7))/(5.15) = 21/75 = 7/25`

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`#LeMichael`

 

Answer 2

Câu 2: 

a: \(=\dfrac{-2}{5}\cdot\dfrac{5}{4}=\dfrac{-2}{4}=\dfrac{-1}{2}\)

b: \(=\dfrac{3}{5}\cdot\dfrac{7}{15}=\dfrac{21}{75}=\dfrac{7}{25}\)

Answer 3

\(\text{a},=\dfrac{2.24-5.15}{360}=-\dfrac{3}{40}\\ b,=\dfrac{\left(-5\right).3-\left(-7\right)}{27}=-\dfrac{8}{27}\\ c,=\left(-\dfrac{7}{12}\right)+\dfrac{3}{4}=\dfrac{-7+3.3}{12}=\dfrac{2}{12}=\dfrac{1}{6}\\ d,=\dfrac{17}{50}+\left(-\dfrac{5}{17}\right)=\dfrac{17.17-5.50}{850}=\dfrac{39}{850}\)