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\(a,\dfrac{90}{108}-\dfrac{40}{72}=\dfrac{5}{6}-\dfrac{5}{9}=\dfrac{30}{36}-\dfrac{20}{36}=\dfrac{10}{36}=\dfrac{5}{18}\)
\(b,\dfrac{59}{8}+\dfrac{21}{4}=\dfrac{59}{8}+\dfrac{42}{8}=\dfrac{101}{8}\)
\(c,\dfrac{25}{2}-\dfrac{18}{13}+\dfrac{5}{13}=\dfrac{325}{26}-\dfrac{26}{26}+\dfrac{10}{26}=\dfrac{309}{26}\)
\(d,\dfrac{17}{13}-\left(\dfrac{25}{100}+\dfrac{4}{13}\right)=\dfrac{17}{13}-\dfrac{29}{52}=\dfrac{3}{4}\)
a) \(\dfrac{90}{108}-\dfrac{40}{72}\)
\(=\dfrac{5}{6}-\dfrac{5}{6}\)
\(=0\)
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-57.11=-627
(+12).(+15)=180
(37-17).(5)+23.(-13-17)=-590
(-4).(+125).(-25).(-6).(-8)=60000
k nha
-57*11=627
12*25=300
(37-17)*5+23*(-13-17)=-665
(-5)*125*(-25)*(-6)*(-8)=750 000
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[25+5] + [19+21] + [13+7] + [4+16] + [17+13] + [10+9]
30+40+20+20+40+19
150+19
169
đúng ko
a] [4+16]+[7+13]+[19+21]+[5+25]+[13+17]+[10+19]
= 20+20+40+30+30+29
=169
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a,(18+29)+(158-18-29)=18+29+158-18-29=158
b,(-13-135+49)-(13+49)=-13-135+49-13-49=-26-135=-161
c,(-25)+15=-10
d,(-99)+(-100)+(-101)+(-102)=-99-100-101-102=-402
e,34+(-11)+(-4)=34-4-11=19
f,134+45+(-14)+(-5)=(134-14)+(45-5)=120+40=160
g,21+(-50)+(-1)=(21-1)-50=20-50=-30
h,44+(-213)+/-156/=44+213+156=(44+156)+213=200+213=413
i,212+[37+(-312)+(-17)]=212+37-312-17=(212-312)+(37-17)=-100+20=-80
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a ) 17 x 4 = ( 15 + 2 ) x 4 = 15 x 4 + 2 x 4 = 60 + 8 = 68
25 x 28 = 25 x ( 20 + 8 ) = 25 x 20 + 25 x 8 = 500 + 200 = 700
b ) 13 x 12 = 13 x ( 10 + 2 ) = 13 x 10 + 13 x 2 = 130 + 26 = 156
53 x 11 = 53 x ( 10 + 1 ) = 53 x 10 + 53 x 1 = 530 + 53 = 583
39 x 101 = 39 x ( 100 + 1 ) = 39 x 100 + 39 x 1 = 3900 + 39 = 3939
a) Ta có:
\(17\times4=\left(15+2\right)\times4=15\times4+2\times4=60+8=68\)
\(25\times28=25\times\left(20+8\right)=25\times20+25\times8=500+200=700\)
b) Ta có:
\(13\times12=13\times\left(10+2\right)=13\times10+13\times2=130+26=156\)
\(53\times11=53\times\left(10+1\right)=53\times10+53\times1=530+53=583\)
\(39\times101=39\times\left(100+1\right)=39\times100+39\times1=3900+39=3939\)
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a/=\(\dfrac{-17}{25}\).(\(\dfrac{20}{33}+\dfrac{13}{3}\))+\(\dfrac{-3}{25}\)
=\(\dfrac{-17}{25}\).\(\dfrac{163}{33}\)+\(\dfrac{-3}{25}\)
=\(\dfrac{-2771}{825}\)+\(\dfrac{-3}{25}\)
=\(\dfrac{-574}{165}\)
KHÔNG BIẾT CÓ ĐÚNG KHÔNG NGHE
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( x + 1) + ( x + 2) = 17
=> 2x + 3 = 17
=> 2x = 14
=> x = 7
b, tương tự
c, ( 4 - x) . 9 - 26 : 13 = 25
=> (4-x) . 9 -26 = 325
=> (4 - x) . 9 = 351
=> 4 - x = 39
=> x = -35
\(-\frac{17}{13}+\left(\frac{25}{101}+\frac{4}{13}\right)\)
\(=-\frac{17}{13}+\frac{25}{101}+\frac{4}{13}\)
\(=\left(-\frac{17}{13}+\frac{4}{13}\right)+\frac{25}{101}\)
\(=1+\frac{25}{101}=\frac{126}{101}\)
\(-\frac{17}{13}+\left(\frac{25}{101}+\frac{4}{13}\right)\)
\(=-\frac{17}{13}+\frac{739}{1313}=-\frac{76}{101}\)
học tốt ~~~