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14 tháng 2 2022
a: \(=\dfrac{-5}{8}+\dfrac{7}{12}=\dfrac{-15}{24}+\dfrac{14}{24}=\dfrac{-1}{24}\)
b: \(=\dfrac{3}{4}-\dfrac{5}{6}+\dfrac{11}{12}=\dfrac{9}{12}-\dfrac{10}{12}+\dfrac{11}{12}=\dfrac{10}{12}=\dfrac{5}{6}\)
c: \(=\dfrac{6}{36}-\dfrac{1}{36}=\dfrac{5}{36}\)
d: \(=\dfrac{5}{12}+\dfrac{5}{12}=\dfrac{10}{12}=\dfrac{5}{6}\)
e: \(=\dfrac{-8}{56}-\dfrac{7}{56}=\dfrac{-15}{56}\)
f: \(=\dfrac{-5}{15}+\dfrac{3}{25}=\dfrac{-25}{75}+\dfrac{9}{75}=\dfrac{-16}{75}\)
I
26 tháng 2 2020
A, (-25). 21. (-2)2. (-|-3|). (-1)2015
B, (-5)3. 67. (-|-2|). (-1)2014
C, 35.18 – 5.7.28 + 35. (-90)
D, 24. (16 – 5) – 16. (24 – 5)
E, - 79. (73 – 27) – 73. (-79 + 27)
G, 31. (-18) + 31. (-8)-31
M, -48 + 48. (-78) + 48. (-21)
N, -|-17| + 2. [ 24: (-8) + (-5)2]
I, -|-7|. [(-2)4 + (-36): (-32)] – (-5)3
HH
1
6 tháng 2 2022
1: \(=\dfrac{-5}{8}\cdot\dfrac{15}{4}=-\dfrac{75}{32}\)
2: \(=\dfrac{15}{17}\cdot\dfrac{25}{34}=\dfrac{375}{578}\)
3: \(=-12\cdot\dfrac{8}{3}=-4\cdot8=-32\)
4: \(=\dfrac{15}{14}\cdot\dfrac{20}{21}=\dfrac{50}{49}\)
5: \(=48\cdot\dfrac{24}{5}=230.4\)
2 tháng 2 2016
\(A=\frac{4}{3}.\frac{9}{8}.\frac{16}{15}.\frac{25}{24}.\frac{36}{35}......\frac{9801}{9800}=\frac{\left(2.3.4.5....99\right)^2}{1.3.2.4.3.5.4.6.....98.100}=\frac{2.3.4.5...99}{1.2.3.4.....98}.\frac{2.3.4.5....99}{3.4.5.6......100}=\frac{99}{1}.\frac{2}{100}=\frac{99}{50}\)
20 tháng 11 2023
a: (-17)+5+8+17
\(=\left(-17+17\right)+\left(5+8\right)\)
=0+13
=13
b: \(\left(-24\right)+6+10+24\)
\(=\left(-24+24\right)+\left(6+10\right)\)
=0+16
=16
c: \(\left(-24\right)+6+\left(-10\right)+24\)
\(=\left(-24+24\right)+\left(6-10\right)\)
=0+(-4)
=-4
d: \(\left(-456\right)+2021-544\)
\(=2021-\left(456+544\right)\)
=2021-1000
=1021
e: \(\left(-1075\right)-29-\left(-1075\right)\)
\(=-1075+1075-29\)
=0-29
=-29
f: \(\left(-135\right)+48+140-\left(-5\right)\)
\(=48+\left(-135+140+5\right)\)
=48+10
=58
g: \(329+64+\left(-394\right)+36\)
\(=\left(329-394\right)+\left(64+36\right)\)
=100-65
=35
h: \(\left(-427\right)+\left(-123\right)+23+27\)
\(=\left(-427+27\right)+\left(-123+23\right)\)
=-400-100
=-500
KT
5 tháng 7 2018
1) \(35.18-5.7.28=35.18-35.28=35\left(18-28\right)=-350\)
2) \(45-5\left(12+9\right)=45-60-45=-60\)
3) \(24\left(16-5\right)-16\left(24-5\right)=24.16-24.5-16.24+16.5=5\left(16-24\right)=5.8=40\)
4) \(29\left(19-13\right)-19\left(29-13\right)=29.19-29.13-19.29+19.13=13\left(19-29\right)=-130\)
KT
5 tháng 7 2018
5) \(31.\left(-18\right)+31.\left(-81\right)-31=-31.\left(18+81+1\right)=-3100\)
6) \(\left(-12\right).47+\left(-12\right).52+\left(-12\right)=\left(-12\right)\left(47+52+1\right)=-1200\)
7) \(13\left(23+22\right)-3\left(17+28\right)=13.45-3.45=45.\left(13-3\right)=450\)
8) \(-48+48.\left(-78\right)+48.\left(-21\right)=-48\left(1+78+21\right)=-4800\)
Ta có: \(A=\dfrac{5}{8}+\dfrac{5}{24}+\dfrac{5}{48}+...+\dfrac{5}{9800}\)
\(=\dfrac{5}{2}\left(\dfrac{2}{8}+\dfrac{2}{24}+\dfrac{2}{48}+...+\dfrac{2}{9800}\right)\)
\(=\dfrac{5}{2}\left(\dfrac{1}{2}-\dfrac{1}{4}+\dfrac{1}{4}-\dfrac{1}{6}+\dfrac{1}{6}-\dfrac{1}{8}+...+\dfrac{1}{98}-\dfrac{1}{100}\right)\)
\(=\dfrac{5}{2}\left(\dfrac{1}{2}-\dfrac{1}{100}\right)\)
\(=\dfrac{5}{2}\cdot\dfrac{49}{50}\)
\(=\dfrac{245}{100}=\dfrac{49}{20}\)