a,2/3 cua 8,7 là:8,7:3.2=5.8
b, 2/7 cua -11/6 là: -11/6.2/7=_11/21
c,2và 1/3=7/3
7/3 cua 5.1 là:5,1 .7/3=11,9
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tính nhanh :a) frac{-3}{7}+frac{15}{26}-left(frac{2}{13}-frac{3}{7}right)b) 2.frac{3}{7}+left(frac{2}{9}-1frac{3}{7}right)-frac{5}{3}:frac{1}{9}c) frac{-11}{23}.frac{6}{7}+frac{8}{7}.frac{-11}{23}-frac{1}{23}d) left(frac{377}{-231}-frac{123}{89}+frac{34}{791}right).left(frac{1}{6}-frac{1}{8}-frac{1}{24}right)
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tính nhanh :
a) \(\frac{-3}{7}+\frac{15}{26}-\left(\frac{2}{13}-\frac{3}{7}\right)\)
b) \(2.\frac{3}{7}+\left(\frac{2}{9}-1\frac{3}{7}\right)-\frac{5}{3}:\frac{1}{9}\)
c) \(\frac{-11}{23}.\frac{6}{7}+\frac{8}{7}.\frac{-11}{23}-\frac{1}{23}\)
d) \(\left(\frac{377}{-231}-\frac{123}{89}+\frac{34}{791}\right).\left(\frac{1}{6}-\frac{1}{8}-\frac{1}{24}\right)\)
Rút gọn
1.left(frac{2}{45}-frac{4}{13}-frac{1}{3}right):left(frac{3}{13}-frac{4}{15}+frac{2}{13}right)
2.frac{0,8:left(frac{4}{5}.1,25right)}{0,64-frac{1}{25}}+frac{left(1,08-frac{2}{15}right):frac{4}{7}}{left(6frac{5}{9}-3frac{1}{4}right)2frac{2}{17}}
3.frac{0,4-frac{2}{9}+frac{2}{11}}{1,4-frac{7}{9}+frac{7}{11}}-frac{frac{1}{3}-0,25+frac{1}{5}}{1frac{1}{6}-0,875+0,7}
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Rút gọn
1.\(\left(\frac{2}{45}-\frac{4}{13}-\frac{1}{3}\right):\left(\frac{3}{13}-\frac{4}{15}+\frac{2}{13}\right)\)
2.\(\frac{0,8:\left(\frac{4}{5}.1,25\right)}{0,64-\frac{1}{25}}+\frac{\left(1,08-\frac{2}{15}\right):\frac{4}{7}}{\left(6\frac{5}{9}-3\frac{1}{4}\right)2\frac{2}{17}}\)
3.\(\frac{0,4-\frac{2}{9}+\frac{2}{11}}{1,4-\frac{7}{9}+\frac{7}{11}}-\frac{\frac{1}{3}-0,25+\frac{1}{5}}{1\frac{1}{6}-0,875+0,7}\)
tính hợp lí ( nếu có thể )Bleft(frac{2}{3}-frac{1}{4}+frac{5}{11}right):left(frac{5}{12}+1-frac{7}{11}right)Cleft(-frac{14}{33}right).2frac{4}{9}+frac{48}{25}:frac{27}{25}Dleft(3-2frac{1}{3}+frac{1}{4}right):left(4-5frac{1}{6}+2frac{1}{4}right)Gleft(7frac{1}{9}-2frac{14}{15}right):left(2frac{2}{3}-6frac{2}{3}right)-frac{32}{45}H-frac{1}{7}.left(9frac{1}{2}-8,75right):frac{2}{7}+0,625:1frac{2}{3}
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tính hợp lí ( nếu có thể )
\(B=\left(\frac{2}{3}-\frac{1}{4}+\frac{5}{11}\right):\left(\frac{5}{12}+1-\frac{7}{11}\right)\)
\(C=\left(-\frac{14}{33}\right).2\frac{4}{9}+\frac{48}{25}:\frac{27}{25}\)
\(D=\left(3-2\frac{1}{3}+\frac{1}{4}\right):\left(4-5\frac{1}{6}+2\frac{1}{4}\right)\)
\(G=\left(7\frac{1}{9}-2\frac{14}{15}\right):\left(2\frac{2}{3}-6\frac{2}{3}\right)-\frac{32}{45}\)
\(H=-\frac{1}{7}.\left(9\frac{1}{2}-8,75\right):\frac{2}{7}+0,625:1\frac{2}{3}\)
tìm x biết :a) left(x+frac{1}{2}right).left(frac{2}{3}-2xright)0b) left(x.6frac{2}{7}+frac{3}{7}right).2frac{1}{5}-frac{3}{7}-2c) x.3frac{1}{4}+left(-frac{7}{6}right).x-1frac{2}{3}frac{5}{12}d) 5frac{8}{17}:x+left(-frac{4}{17}right):x+3frac{1}{7}:17frac{1}{3}frac{4}{11}e) frac{17}{2}-left|2x-frac{3}{4}right|-frac{7}{4}
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tìm x biết :
a) \(\left(x+\frac{1}{2}\right).\left(\frac{2}{3}-2x\right)=0\)
b) \(\left(x.6\frac{2}{7}+\frac{3}{7}\right).2\frac{1}{5}-\frac{3}{7}=-2\)
c) \(x.3\frac{1}{4}+\left(-\frac{7}{6}\right).x-1\frac{2}{3}=\frac{5}{12}\)
d) \(5\frac{8}{17}:x+\left(-\frac{4}{17}\right):x+3\frac{1}{7}:17\frac{1}{3}=\frac{4}{11}\)
e) \(\frac{17}{2}-\left|2x-\frac{3}{4}\right|=-\frac{7}{4}\)
Tính giá trị của biểu thức, tính nhanh nếu có thể13) frac{2}{3}+frac{2}{15}+frac{2}{35}+frac{2}{63}14) frac{2}{35}+frac{4}{47}+frac{2}{143}+frac{4}{221}+frac{2}{323}+frac{4}{437}+frac{2}{575}15) frac{5}{3}-frac{5}{6}+frac{1}{2}B ___________ frac{9}{10}+frac{13}{30} frac{1}{3}-frac{1}{5}+frac{1}{7} frac{6}{5}+frac{6}{11}-frac{6}{13}16) 162 . ( ____________ + ____________ frac{7}{3}-frac{7}{5}+1 ...
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Tính giá trị của biểu thức, tính nhanh nếu có thể
13) \(\frac{2}{3}+\frac{2}{15}+\frac{2}{35}+\frac{2}{63}\)
14) \(\frac{2}{35}+\frac{4}{47}+\frac{2}{143}+\frac{4}{221}+\frac{2}{323}+\frac{4}{437}+\frac{2}{575}\)
15) \(\frac{5}{3}-\frac{5}{6}+\frac{1}{2}\)
B = ___________
\(\frac{9}{10}+\frac{13}{30}\)
\(\frac{1}{3}-\frac{1}{5}+\frac{1}{7}\) \(\frac{6}{5}+\frac{6}{11}-\frac{6}{13}\)
16) 162 . ( ____________ + ____________
\(\frac{7}{3}-\frac{7}{5}+1\) \(\frac{7}{5}+\frac{7}{11}-\frac{7}{13}\)
Tính giá trị của biểu thức, tính nhanh nếu có thể9) frac{13}{50} + 9% + frac{41}{100} + 24%10) 2011,2012 . 2000 ( frac{5}{6} - frac{1}{3} - 50% ) . 1,234 + 1011) frac{120-0,5.40.5.0,2.20.0,25-20}{1+5+9+........+33+37}12) 6frac{2}{7}+7frac{3}{5}+8frac{6}{9}+9frac{1}{4}+frac{2}{5}+frac{5}{7}+frac{1}{3}+frac{3}{4}+1997
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Tính giá trị của biểu thức, tính nhanh nếu có thể
9) \(\frac{13}{50}\) + 9% + \(\frac{41}{100}\) + 24%
10) 2011,2012 . 2000 ( \(\frac{5}{6}\) - \(\frac{1}{3}\) - 50% ) . 1,234 + 10
11) \(\frac{120-0,5.40.5.0,2.20.0,25-20}{1+5+9+........+33+37}\)
12) \(6\frac{2}{7}+7\frac{3}{5}+8\frac{6}{9}+9\frac{1}{4}+\frac{2}{5}+\frac{5}{7}+\frac{1}{3}+\frac{3}{4}+1997\)
Rút gọn
1.\(\frac{7}{19}.\frac{8}{11}+\frac{7}{19}.\frac{3}{11}+\frac{12}{19}\)
2.\(\frac{\frac{2}{5}+\frac{2}{7}-\frac{2}{9}-\frac{2}{11}}{\frac{4}{5}+\frac{4}{7}-\frac{4}{9}-\frac{4}{11}}\)
tính hợp lí nếu có thể
\(-\frac{1}{4}\times13\frac{9}{11}-0,25\times6\frac{2}{11}\)
\(B=\frac{-5}{6}\times\frac{4}{19}+\frac{-7}{12}\times\frac{4}{19}-\frac{40}{57}\)
\(\frac{3}{7}\times\frac{9}{26}-\frac{1}{14}\times\frac{1}{13}-\frac{1}{7}\)
\(\frac{4}{9}:\left(-\frac{1}{7}\right)+6\frac{5}{9}:\left(-\frac{1}{7}\right)\)
Bài 1: Thực hiện phép tính 1 cách hợp lý : a) left(1+frac{1}{1.3}right).left(1+frac{1}{2.4}right).left(1+frac{1}{3.5}right)...left(1+frac{1}{2009.2011}right)b) frac{16}{9}-frac{1}{36}-frac{1}{28}-frac{1}{21}-frac{1}{15}-frac{1}{10}-frac{1}{6}-frac{1}{3}-1 c) frac{0,4-frac{2}{9}+frac{2}{11}-frac{2}{37}}{1,4-frac{7}{9}-frac{7}{11}-frac{7}{37}}-frac{frac{1}{3}-0,25+frac{1}{5}}{1frac{1}{6}-0,785+0,7}
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Bài 1: Thực hiện phép tính 1 cách hợp lý :
\(a\)) \(\left(1+\frac{1}{1.3}\right).\left(1+\frac{1}{2.4}\right).\left(1+\frac{1}{3.5}\right)...\left(1+\frac{1}{2009.2011}\right)\)
\(b\)) \(\frac{16}{9}-\frac{1}{36}-\frac{1}{28}-\frac{1}{21}-\frac{1}{15}-\frac{1}{10}-\frac{1}{6}-\frac{1}{3}-1\)
\(c\)) \(\frac{0,4-\frac{2}{9}+\frac{2}{11}-\frac{2}{37}}{1,4-\frac{7}{9}-\frac{7}{11}-\frac{7}{37}}-\frac{\frac{1}{3}-0,25+\frac{1}{5}}{1\frac{1}{6}-0,785+0,7}\)