BT1: Tính nhanh:
1) \(\dfrac{5}{7}.\dfrac{-4}{19}-\dfrac{10}{7}.\dfrac{15}{38}\)
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BT1: Tính nhanh
1) \(\left(\dfrac{-4}{9}+\dfrac{3}{7}\right):1\dfrac{1}{15}+\left(\dfrac{4}{7}-\dfrac{5}{9}\right):1\dfrac{1}{15}\)
2) \(3\dfrac{2}{9}.15\dfrac{4}{7}-3\dfrac{2}{9}.8\dfrac{1}{7}+3\dfrac{2}{9}.\dfrac{15}{7}-3\dfrac{2}{9}.\dfrac{1}{7}\)
1: \(=\dfrac{16}{15}\left(-\dfrac{4}{9}+\dfrac{3}{7}\right)+\dfrac{16}{15}\left(\dfrac{4}{7}-\dfrac{5}{9}\right)\)
\(=\dfrac{16}{15}\left(-\dfrac{4}{9}+\dfrac{3}{7}+\dfrac{4}{7}-\dfrac{5}{9}\right)=0\)
2: \(=\dfrac{29}{9}\left(15+\dfrac{4}{7}-8-\dfrac{1}{7}+\dfrac{15}{7}-\dfrac{1}{7}\right)\)
\(=\dfrac{20}{9}\cdot\left(7\cdot\dfrac{18}{7}\right)=\dfrac{20}{9}\cdot18=40\)
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8. dfrac{-5}{9} + dfrac{8}{15} + dfrac{-2}{11} + dfrac{4}{-9} + dfrac{7}{15}9. dfrac{2}{7} + (dfrac{-2}{5} + dfrac{5}{7})10. dfrac{7}{19}. dfrac{8}{11} + dfrac{3}{11}.dfrac{7}{19}+dfrac{-12}{19}11. dfrac{-5}{7}.dfrac{2}{11} + dfrac{-5}{7}.dfrac{9}{11}12. dfrac{-5}{13} + dfrac{5}{7} + dfrac{20}{41} + dfrac{-8}{13} + dfrac{21}{41}Giúp tớ với ạ! Tớ cảm ơn! Các cậu chỉ cần ghi đáp án cuối cùng thôi ạ! Cảm ơn các cậu3
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8. \(\dfrac{-5}{9}\) + \(\dfrac{8}{15}\) + \(\dfrac{-2}{11}\) + \(\dfrac{4}{-9}\) + \(\dfrac{7}{15}\)
9. \(\dfrac{2}{7}\) + (\(\dfrac{-2}{5}\) + \(\dfrac{5}{7}\))
10. \(\dfrac{7}{19}\). \(\dfrac{8}{11}\) + \(\dfrac{3}{11}\).\(\dfrac{7}{19}\)+\(\dfrac{-12}{19}\)
11. \(\dfrac{-5}{7}\).\(\dfrac{2}{11}\) + \(\dfrac{-5}{7}\).\(\dfrac{9}{11}\)
12. \(\dfrac{-5}{13}\) + \(\dfrac{5}{7}\) + \(\dfrac{20}{41}\) + \(\dfrac{-8}{13}\) + \(\dfrac{21}{41}\)
Giúp tớ với ạ! Tớ cảm ơn! Các cậu chỉ cần ghi đáp án cuối cùng thôi ạ! Cảm ơn các cậu<3
8: \(=\dfrac{-5}{9}-\dfrac{4}{9}+\dfrac{8}{15}+\dfrac{7}{15}-\dfrac{2}{11}=\dfrac{-2}{11}\)
9: =2/7-2/5+5/7=1-2/5=3/5
10: \(=\dfrac{7}{19}\left(\dfrac{8}{11}+\dfrac{3}{11}\right)-\dfrac{12}{19}=\dfrac{-5}{19}\)
11: \(=\dfrac{-5}{7}\left(\dfrac{2}{11}+\dfrac{9}{11}\right)=\dfrac{-5}{7}\)
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8 = -2/11
9 = 3/5
10 = -5/19
11 = -5/7
11 = 5/13
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BT1: Tính
1) \(\dfrac{7}{80}:\dfrac{\left(-7\right)}{4}-\dfrac{2}{9}:\left(8-\dfrac{8}{3}\right)-\dfrac{\left(-5\right)}{24}.\left(\dfrac{\left(-10\right)}{3}+\dfrac{38}{15}\right)^2\)
2) 1500 - {5\(^3\) . 2\(^3\)- 11 . [ 7\(^2\) - 5. 2\(^3\) + 8 ( 11\(^2\) - 121)]}
1: \(=-\dfrac{7}{80}\cdot\dfrac{4}{7}-\dfrac{2}{9}:\dfrac{16}{3}+\dfrac{5}{24}\cdot\left(\dfrac{-50+38}{15}\right)^2\)
\(=\dfrac{-1}{20}-\dfrac{2}{9}\cdot\dfrac{3}{16}+\dfrac{5}{24}\cdot\dfrac{16}{25}\)
\(=\dfrac{-1}{20}-\dfrac{1}{24}+\dfrac{2}{15}\)
\(=\dfrac{-6-5+16}{120}=\dfrac{5}{120}=\dfrac{1}{24}\)
2: \(=1500-\left\{10^3-11\cdot\left[49-5\cdot8\right]\right\}\)
\(=1500-\left\{1000-11\cdot9\right\}\)
\(=1500-1000+99=599\)
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Tính nhanh
\(\dfrac{4}{7}.\dfrac{89}{5}-\dfrac{4}{5}.\dfrac{82}{7}\)
\(\dfrac{5}{7}.\dfrac{-4}{19}+\dfrac{-15}{7}.\dfrac{5}{19}\)
\(\dfrac{4}{7}.\dfrac{89}{5}-\dfrac{4}{5}.\dfrac{82}{7}\)
\(=\dfrac{4}{7}.\dfrac{89}{5}-\dfrac{4}{7}.\dfrac{82}{5}\)
\(=\dfrac{4}{7}.\left(\dfrac{89}{5}-\dfrac{82}{5}\right)\)
\(=\dfrac{4}{7}.\dfrac{7}{5}\)
\(=\dfrac{4}{5}\)
\(\dfrac{5}{7}.\dfrac{-4}{19}+\dfrac{-15}{7}.\dfrac{5}{19}\)
\(=\dfrac{5}{7}.\dfrac{-4}{19}+\dfrac{5}{7}.\dfrac{-15}{19}\)
\(=\dfrac{5}{7}.\left(\dfrac{-4}{19}+\dfrac{-15}{19}\right)\)
\(=\dfrac{5}{7}.\left(-1\right)\)
\(=\dfrac{-5}{7}\)
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12 tháng 3 2022 lúc 14:25
Tính bằng cách hợp lý:a,dfrac{2}{3}+left(dfrac{5}{7}+dfrac{-2}{3}right) b,left(dfrac{-1}{4}+dfrac{5}{8}right)+dfrac{-3}{8}c,dfrac{7}{5}.dfrac{8}{19}+dfrac{7}{5}.dfrac{12}{19}-dfrac{7}{5}.dfrac{1}{19}d,6dfrac{3}{10}-left(3dfrac{4}{7}+2dfrac{3}{10}right)e,left(31,12-5,97right)-left(-68,88+4,03right)h,3,7.left(-10,56right)+3,7.110,56
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Tính bằng cách hợp lý:
\(a,\dfrac{2}{3}+\left(\dfrac{5}{7}+\dfrac{-2}{3}\right)\)
\(b,\left(\dfrac{-1}{4}+\dfrac{5}{8}\right)+\dfrac{-3}{8}\)
\(c,\dfrac{7}{5}.\dfrac{8}{19}+\dfrac{7}{5}.\dfrac{12}{19}-\dfrac{7}{5}.\dfrac{1}{19}\)
\(d,6\dfrac{3}{10}-\left(3\dfrac{4}{7}+2\dfrac{3}{10}\right)\)
\(e,\left(31,12-5,97\right)-\left(-68,88+4,03\right)\)
\(h,3,7.\left(-10,56\right)+3,7.110,56\)
Làm giúp em với ạ
\(M=\dfrac{\left(\dfrac{3}{10}-\dfrac{4}{15}-\dfrac{7}{20}\right)•\dfrac{5}{19}}{\left(\dfrac{1}{17}+\dfrac{1}{7}-\dfrac{-3}{35}\right)•\dfrac{-4}{35}}\)
Tính Nhanh Nha Mọi người
Sửa đề: \(M=\dfrac{\left(\dfrac{3}{10}-\dfrac{4}{15}-\dfrac{7}{20}\right)\cdot\dfrac{5}{19}}{\left(\dfrac{1}{5}+\dfrac{1}{7}-\dfrac{-3}{35}\right)\cdot\dfrac{-4}{45}}\)
\(=\dfrac{\dfrac{3\cdot6-4\cdot4-7\cdot3}{60}\cdot\dfrac{5}{19}}{\dfrac{7+5+3}{35}\cdot\dfrac{-4}{45}}=\dfrac{\dfrac{-19}{60}\cdot\dfrac{5}{19}}{\dfrac{15}{35}\cdot\dfrac{-4}{45}}=\dfrac{-1}{12}:\dfrac{-4}{105}=\dfrac{105}{60}=\dfrac{7}{4}\)
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Thực hiện phép tính (tính nhanh nếu có thể)
a) -19+7+9+19
b) \(11\dfrac{3}{13}-\left(2\dfrac{4}{7}+5\dfrac{3}{13}\right)\)
c) \(\dfrac{2}{7}.5\dfrac{1}{4}-\dfrac{2}{7}.3\dfrac{1}{4}\)
a: =9+7=16
b: =11+3/13-2-4/7-5-3/13
=4-4/7
=28/7-4/7=24/7
c: =2/7(5+1/4-3-1/4)=2/7x2=4/7
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BT1: Tính nhanh
2) \(\left(7-\dfrac{4}{3}+\dfrac{1}{3}\right)-\left(6+\dfrac{5}{4}-\dfrac{4}{3}\right)-\left(5-\dfrac{7}{4}+\dfrac{5}{3}\right)\)
\(=7-\dfrac{4}{3}+\dfrac{1}{3}-6-\dfrac{5}{4}+\dfrac{4}{3}-5+\dfrac{7}{4}-\dfrac{5}{3}\)
\(=\left(7-6-5\right)-\left(\dfrac{4}{3}-\dfrac{4}{3}+\dfrac{5}{3}-\dfrac{1}{3}\right)-\left(\dfrac{5}{4}-\dfrac{7}{4}\right)\)
\(=-4-\dfrac{4}{3}-\left(\dfrac{-1}{2}\right)\)
\(=-4-\dfrac{4}{3}+\dfrac{1}{2}\)
\(=-\dfrac{24}{6}-\dfrac{8}{6}+\dfrac{3}{6}\)
\(=-\dfrac{32}{6}+\dfrac{3}{6}\)
\(=-\dfrac{29}{6}\)
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27 tháng 1 2022 lúc 10:01
Tính giá trị biểu thứca, 19dfrac{5}{8}:dfrac{7}{12}-15dfrac{1}{4}:dfrac{7}{12} b,dfrac{2}{5}.dfrac{1}{3}-dfrac{2}{15}:dfrac{1}{5}+dfrac{3}{5}.dfrac{1}{3}c, left(3dfrac{1}{3}+2,5right):left(3dfrac{1}{6}-4dfrac{1}{5}right)-dfrac{11}{31} d, left[6+left(dfrac{1}{2}right)^3-left|-dfrac{1}{2}right|right]:dfrac{3}{12}
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Tính giá trị biểu thức
a, \(19\dfrac{5}{8}:\dfrac{7}{12}-15\dfrac{1}{4}:\dfrac{7}{12}\) b,\(\dfrac{2}{5}.\dfrac{1}{3}-\dfrac{2}{15}:\dfrac{1}{5}+\dfrac{3}{5}.\dfrac{1}{3}\)
c, \(\left(3\dfrac{1}{3}+2,5\right):\left(3\dfrac{1}{6}-4\dfrac{1}{5}\right)-\dfrac{11}{31}\) d, \(\left[6+\left(\dfrac{1}{2}\right)^3-\left|-\dfrac{1}{2}\right|\right]:\dfrac{3}{12}\)
a) \(=\dfrac{157}{8}.\dfrac{12}{7}-\dfrac{61}{4}.\dfrac{12}{7}=\dfrac{12}{7}\left(\dfrac{157}{8}-\dfrac{61}{4}\right)=\dfrac{12}{7}.\dfrac{35}{8}=\dfrac{15}{2}\)
b) \(\dfrac{2}{5}.\dfrac{1}{3}-\dfrac{2}{15}\div\dfrac{1}{5}+\dfrac{3}{5}.\dfrac{1}{3}=\dfrac{1}{3}\left(\dfrac{2}{5}+\dfrac{3}{5}\right)-\dfrac{2}{15}.5=\dfrac{1}{3}.1-\dfrac{2}{3}=\dfrac{1}{3}-\dfrac{2}{3}=-\dfrac{1}{3}\)
c) \(=-\dfrac{80}{9}\)
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a.=\(\dfrac{157}{8}:\dfrac{7}{12}-\dfrac{61}{4}:\dfrac{7}{12}=\dfrac{471}{14}-\dfrac{183}{7}=\dfrac{15}{2}\)
b.=\(\dfrac{2}{15}-\dfrac{2}{3}+\dfrac{1}{5}=-\dfrac{1}{3}\)
c.\(\left(\dfrac{10}{3}+2.5\right):\left(\dfrac{19}{6}-\dfrac{21}{5}\right)-\dfrac{11}{31}=\dfrac{35}{6}:\left(-\dfrac{31}{30}\right)-\dfrac{11}{31}=-\dfrac{175}{31}-\dfrac{11}{31}=-6\)
d.\(\left[6+\dfrac{1}{8}-\dfrac{1}{2}\right]:\dfrac{3}{12}=\dfrac{45}{8}:\dfrac{3}{12}=\dfrac{45}{2}\)
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