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Bài 1:
a: =25+75=100
b: =60-17-43+12=12
c: =-2-18=-20
d: =-3+36-17=36-20=16
Bài 2:
a: =-102
b: =-1000
c: =12x15=180
d: =21x(-10)=-210
Giải:
a) \(\left(9\dfrac{4}{9}+5\dfrac{2}{3}\right)-5\dfrac{1}{2}\)
\(=\left(\dfrac{85}{9}+\dfrac{17}{3}\right)-\dfrac{11}{2}\)
\(=\dfrac{136}{9}-\dfrac{11}{2}\)
\(=\dfrac{173}{18}\)
b) \(\dfrac{13}{9}.\dfrac{15}{4}-\dfrac{13}{9}.\dfrac{7}{4}-\dfrac{13}{9}.\dfrac{5}{4}\)
\(=\dfrac{13}{9}.\left(\dfrac{15}{4}-\dfrac{7}{4}-\dfrac{5}{4}\right)\)
\(=\dfrac{13}{9}.\dfrac{3}{4}\)
\(=\dfrac{13}{12}\)
c) \(\dfrac{2}{3}+\dfrac{5}{8}-\dfrac{-1}{3}+0,375\)
\(=\left(\dfrac{2}{3}-\dfrac{-1}{3}\right)+\left(\dfrac{5}{8}+\dfrac{3}{8}\right)\)
\(=1+1\)
\(=2\)
d) \(75\%-3\dfrac{1}{2}+1,5:\dfrac{10}{7}\)
\(=\dfrac{3}{4}+\dfrac{7}{2}+\dfrac{3}{2}:\dfrac{10}{7}\)
\(=\dfrac{3}{4}+\dfrac{7}{2}+\dfrac{21}{20}\)
\(=\dfrac{53}{10}\)
e) \(1\dfrac{13}{15}.\left(0,5\right)^2.3+\left(\dfrac{8}{15}-1\dfrac{19}{60}\right):1\dfrac{23}{24}\)
\(=\dfrac{28}{15}.\dfrac{1}{4}.3+\left(\dfrac{8}{15}-\dfrac{79}{60}\right):\dfrac{47}{24}\)
\(=\dfrac{7}{5}+\dfrac{-47}{60}:\dfrac{47}{24}\)
\(=\dfrac{7}{5}+\dfrac{-2}{5}\)
\(=1\)
1) 10 - 3 ( x - 1 ) = -5
3 ( x - 1 ) = 10 - ( - 5 )
3 ( x - 1 ) = 15
x - 1 = 15 : 3
x - 1 = 5
x = 5 + 1
x = 6
2) 3x + 75 = - 15
3x = - 15 - 75
3x = - 90
x = -90 : 3
x = -30
4) 12 - ( x - 7 ) = - 8
x - 7 = 12 - (- 8 )
x - 7 = 20
x = 20 + 7
x = 27
5) x + 75 = 15
x = 15 - 75
x = -60
7) 2x + 18 = 10
2x = 10 - 18
2x = -8
x = - 8 : 2
x = -4
8) 26 - 3x = 5
3x = 26 - 5
3x = 21
x = 21: 3
x = 7
9) x - 12 = - 15
x = -15 + 12
x =-3
10 ) 24 - 2 ( x + 5 ) = 38
2 ( x+ 5 ) = 24 - 38
2 ( x + 5 ) = - 14
x + 5 = -14 : 2
x + 5 = -7
x = -7 - 5
x = -12
còn là bạn tự làm tiếp nhé ! bạn gửi nhiều cầu qua bạn chỉ nên gửi ít một thời như vậy khó có thể giải làm bạn ạ!
Câu 1:
a) -8 + 5 = \(-3\)
b) -6 - 10 = \(-16\)
c) (-50) . (-9) \(=-450\)
d) (-45) : 9 \(=-5\)
e) 24 . 125 + 24 . 75 = 24 .( 125 + 75 ) = 24 . 200 = 4800
g) 42 - 7 . 25 = 42 - 175 = -133
h) (5-7) . 11 = -2 . 11 = -22
i) (-3 - 12) : (-5) = -15 : (-5) = 3
k) 3 . (-4)^2 + 2 . (-5) = 3. 16 + -10 = 48 + (-10 ) = 38
l) 125 . (-15) . 8 = -1875 . 8 = -15000
a, -8 + 5 = -3
b, -6 - 10 = -16
c, -50 . (-9) = 450
d, (-45) : 9 = -5
e, 24 . 125 +24 . 75 = 24. (125 + 75)
=24. 200 = 4800
g, 42 - 7 . 25 = 42 - 175
= -133
h, (5-7) . 11 = -2 .11
= -22
i, (-3 -12) : (-5) = (-15) : (-5)
= -3
k, 3 . \(\left(-4\right)^2\) + 2 . (-5) = 3 . 16 + (-10)
= 48 + (-10) = 38
l, 125 . (-15) . 8 = (125 . 8) .(-15)
= 1000 . (-15) = -15000
Tick cho mk nha! 
2) 
3) 
4) 
`@` `\text {Ans}`
`\downarrow`
`1,`
`a)`
`-7/25 + (-8)/25`
`= (-7 - 8)/25`
`= -15/25`
`= -3/5`
`b)`
`6/13 + (-15)/39`
`= 18/39 + (-15)/39`
`= (18 - 15)/39`
`= 3/39`
`= 1/13`
`c)`
`5/7 + 4/(-14)`
`= 10/14 + (-4)/14`
`= (10 - 4)/14`
`= 6/14`
`= 3/7`
`d)`
`-8/18 + (-15)/27`
`= -4/9 + (-5)/9`
`= (-4-5)/9`
`= -9/9 = -1`
`2,`
`a)`
`3/5 + (-7)/4`
`= 12/20 + (-35)/20`
`= (12 - 35)/20`
`=-23/20`
`b)`
`(-2) + (-5)/8`
`= (-16)/8 + (-5)/8`
`= (-16 - 5)/8`
`= -21/8`
`c)`
`1/8 + (-5)/9`
`= 9/72 + (-40)/72`
`= (9-40)/72`
`= -31/72`
`d)`
`6/13 + (-14)/39`
`= 18/39 + (-14)/39`
`= (18 - 14)/39`
`= 4/39`
`e)`
`(-18)/24 + 15/21`
`= (-3)/4 + 5/7`
`= (-21)/28 + 20/28`
`= (-21 + 20)/28`
`= -1/28`
`@` `\text {Ans}`
`\downarrow`
`a)`
\(\left(\dfrac{7}{8}-\dfrac{3}{4}\right)\cdot1\dfrac{1}{3}-\dfrac{2}{3}\cdot0,5\)
`=`\(\dfrac{1}{8}\cdot\dfrac{4}{3}-\dfrac{1}{3}\)
`=`\(\dfrac{1}{6}-\dfrac{1}{3}=-\dfrac{1}{6}\)
`b)`
\(\left(2+\dfrac{5}{6}\right)\div1\dfrac{1}{5}+\left(-\dfrac{7}{12}\right)\)
`=`\(\dfrac{17}{6}\div1\dfrac{1}{5}-\dfrac{7}{12}\)
`=`\(\dfrac{85}{36}-\dfrac{7}{12}=\dfrac{16}{9}\)
`c)`
\(75\%-1\dfrac{1}{2}+0,5\div\dfrac{5}{12}\)
`=`\(-\dfrac{3}{4}+\dfrac{6}{5}=\dfrac{9}{20}\)
a) \(\left(\dfrac{7}{8}-\dfrac{3}{4}\right).1\dfrac{1}{3}-\dfrac{2}{3}.0,5\)
\(=\left(\dfrac{7}{8}-\dfrac{6}{8}\right).\dfrac{4}{3}-\dfrac{2}{3}.\dfrac{1}{2}\)
\(=\dfrac{1}{8}.\dfrac{4}{3}-\dfrac{2}{3}.\dfrac{1}{2}\)
\(=\dfrac{1}{6}-\dfrac{1}{3}\)
\(=\dfrac{-1}{6}\)
b) \(\left(2+\dfrac{5}{6}\right):1\dfrac{1}{5}+\dfrac{-7}{12}\)
\(=\left(\dfrac{12}{6}+\dfrac{5}{6}\right):\dfrac{6}{5}+\dfrac{-7}{12}\)
\(=\dfrac{17}{6}.\dfrac{5}{6}+\dfrac{-7}{12}\)
\(=\dfrac{85}{36}+\dfrac{-7}{12}\)
\(=\dfrac{16}{9}\)
c) \(75\%-1\dfrac{1}{2}+0,5:\dfrac{5}{12}\)
\(=\dfrac{3}{4}-\dfrac{3}{2}+\dfrac{1}{2}.\dfrac{12}{5}\)
\(=\dfrac{3}{4}-\dfrac{6}{4}+\dfrac{6}{5}\)
\(=\dfrac{-3}{4}+\dfrac{6}{5}\)
\(=\dfrac{9}{20}\)
a) -2003 + ( -21 + 75 + 2003) = ( -2003 + 2003) + ( -21 + 75 )
= 0 + 54 = 54
b) 942 - 2567 + 2563 - 1942 = ( 942 - 1942 ) + ( -2567 + 2563 )
= -1000 + ( -4)
= - 1004
a) − 5 24 + 0 , 75 + 7 12 : − 2 1 8 = − 5 24 + 3 4 + 7 12 : − 17 8 = 9 8 . − 8 17 = − 9 17 .
b) 75 % - 3 1 2 + 1,5 : 10 7 = 3 4 − 5 2 + 3 2 : 7 10 = 3 4 − 5 2 + 3 2 . 7 10 = − 14 20 = − 7 10 .