=2(1/12+1/30+...+1/132)
=2(1/3-1/4+1/5-1/6+1/6-1/7+...+1/11-1/12)
=2(1/12+1/5-1/12)
=2*1/5=2/5
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Tính nhanh
a, S dfrac{1}{3} + dfrac{1}{15} + dfrac{1}{35} + dfrac{1}{63} + dfrac{1}{99} + dfrac{1}{143}
b, A dfrac{1}{3} + dfrac{1}{6} + dfrac{1}{10} + dfrac{1}{15} + dfrac{1}{21} + dfrac{1}{28}
c, H dfrac{4047991-2010x2009}{4050000-2011x2009}
d, T dfrac{2009x20010+2000}{2011x2010-2020}
e, P dfrac{7589-80,5x69,3}{7485,05-79x69,3}
f, B 5,1 x 42,2 + 1,7 x 448 x 3 - 0,15 x 700
Giúp mình với
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Tính nhanh
a, S= \(\dfrac{1}{3}\) + \(\dfrac{1}{15}\) + \(\dfrac{1}{35}\) + \(\dfrac{1}{63}\) + \(\dfrac{1}{99}\) + \(\dfrac{1}{143}\)
b, A = \(\dfrac{1}{3}\) + \(\dfrac{1}{6}\) + \(\dfrac{1}{10}\) + \(\dfrac{1}{15}\) + \(\dfrac{1}{21}\) + \(\dfrac{1}{28}\)
c, H =\(\dfrac{4047991-2010x2009}{4050000-2011x2009}\)
d, T = \(\dfrac{2009x20010+2000}{2011x2010-2020}\)
e, P = \(\dfrac{7589-80,5x69,3}{7485,05-79x69,3}\)
f, B = 5,1 x 42,2 + 1,7 x 448 x 3 - 0,15 x 700
Giúp mình với
\(A=\dfrac{1}{15}+\dfrac{1}{35}+\dfrac{1}{65}+...+\dfrac{1}{99}=\dfrac{16}{x}\)
\(B=\dfrac{5}{6}+\dfrac{11}{12}+\dfrac{19}{20}+\dfrac{29}{30}+\dfrac{41}{42}+\dfrac{55}{56}+\dfrac{x}{16}\)\(C=\left(1-\dfrac{1}{4}\right)\times\left(1-\dfrac{1}{9}\right)\times\left(1-\dfrac{1}{16}\right)\times...\times\left(1-\dfrac{1}{100}\right)=\dfrac{22}{x}\)
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10 tháng 3 2022 lúc 9:18
Tính hợp lí :A dfrac{-2}{9} + dfrac{-3}{4} + dfrac{3}{5} + dfrac{1}{15} + dfrac{1}{57} + dfrac{1}{3} + dfrac{-1}{36}B dfrac{1}{2} + dfrac{-1}{5} + dfrac{-5}{7} + dfrac{1}{6} + dfrac{-3}{35} + dfrac{1}{3} + dfrac{1}{41}C dfrac{-1}{2} + dfrac{3}{5} + dfrac{-1}{9} + dfrac{1}{127} + dfrac{-7}{18} + dfrac{4}{35} + dfrac{2}{7}
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Tính hợp lí :
A = \(\dfrac{-2}{9}\) + \(\dfrac{-3}{4}\) + \(\dfrac{3}{5}\) + \(\dfrac{1}{15}\) + \(\dfrac{1}{57}\) + \(\dfrac{1}{3}\) + \(\dfrac{-1}{36}\)
B = \(\dfrac{1}{2}\) + \(\dfrac{-1}{5}\) + \(\dfrac{-5}{7}\) + \(\dfrac{1}{6}\) + \(\dfrac{-3}{35}\) + \(\dfrac{1}{3}\) + \(\dfrac{1}{41}\)
C = \(\dfrac{-1}{2}\) + \(\dfrac{3}{5}\) + \(\dfrac{-1}{9}\) + \(\dfrac{1}{127}\) + \(\dfrac{-7}{18}\) + \(\dfrac{4}{35}\) + \(\dfrac{2}{7}\)
dfrac{15}{14} : dfrac{10}{21} x dfrac{1}{5}
5 x dfrac{1}{5} + dfrac{1}{5}
7 : dfrac{1}{5} - dfrac{1}{5}
6 + dfrac{1}{5} : 2
8 - dfrac{1}{5} x 7
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\(\dfrac{15}{14}\) : \(\dfrac{10}{21}\) x \(\dfrac{1}{5}\)
\(5\) x \(\dfrac{1}{5}\) + \(\dfrac{1}{5}\)
\(7\) : \(\dfrac{1}{5}\) - \(\dfrac{1}{5}\)
\(6\) + \(\dfrac{1}{5}\) : \(2\)
\(8\) - \(\dfrac{1}{5}\) x \(7\)
\(\dfrac{\left(\dfrac{1}{6}+\dfrac{1}{10}+\dfrac{1}{15}\right):\left(\dfrac{1}{6}+\dfrac{1}{10}-\dfrac{1}{15}\right)}{\left(\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{4}-\dfrac{1}{5}\right):\left(\dfrac{1}{4}-\dfrac{1}{6}\right)}=\)
\(\dfrac{y}{2022}-\dfrac{1}{10}-\dfrac{1}{15}-\dfrac{1}{21}-...-\dfrac{1}{120}=\dfrac{5}{8}\)
16 tháng 10 2021 lúc 15:24
VÒNG 2Bài 1: Mèo con nhanh nhẹndfrac{1}{2} + dfrac{1}{12}2 + dfrac{1}{6}dfrac{1}{20}1 - dfrac{1}{9} dfrac{1}{15} + dfrac{2}{15}dfrac{1}{2} + dfrac{2}{3}dfrac{7}{12}dfrac{4}{12} dfrac{9}{14}+ dfrac{1}{14}1 + dfrac{1}{6}dfrac{1}{4} - dfrac{1}{5}dfrac{1}{3} - dfrac{2}{9} dfrac{3}{2} + dfrac{2}{3}dfrac{1}{5}1 - dfrac{8}{9} dfrac{5}{7}1 - dfrac{2}{3}dfrac{1}{3} + dfrac{5}{9}
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VÒNG 2
Bài 1: Mèo con nhanh nhẹn
| \(\dfrac{1}{2}\) + \(\dfrac{1}{12}\) | 2 + \(\dfrac{1}{6}\) | \(\dfrac{1}{20}\) | 1 - \(\dfrac{1}{9}\) | |
| \(\dfrac{1}{15}\) + \(\dfrac{2}{15}\) | \(\dfrac{1}{2}\) + \(\dfrac{2}{3}\) | \(\dfrac{7}{12}\) | \(\dfrac{4}{12}\) | |
| \(\dfrac{9}{14}\)+ \(\dfrac{1}{14}\) | 1 + \(\dfrac{1}{6}\) | \(\dfrac{1}{4}\) - \(\dfrac{1}{5}\) | \(\dfrac{1}{3}\) - \(\dfrac{2}{9}\) | |
| \(\dfrac{3}{2}\) + \(\dfrac{2}{3}\) | \(\dfrac{1}{5}\) | 1 - \(\dfrac{8}{9}\) | ||
| \(\dfrac{5}{7}\) | 1 - \(\dfrac{2}{3}\) | \(\dfrac{1}{3}\) + \(\dfrac{5}{9}\) |
\(\dfrac{2}{5}\)*\(15\dfrac{1}{3}\)-\(\dfrac{2}{5}\)*\(10\dfrac{1}{3}\)
\(12\dfrac{5}{11}\)-(\(3\dfrac{1}{4}\)+\(2\dfrac{5}{11}\)]
\(\dfrac{34}{31}\)-\(\dfrac{19}{28}\)-\(\dfrac{3}{31}\)
\(\dfrac{8\dfrac{1}{2}}{15:\dfrac{5}{17}}\) \(\dfrac{4\dfrac{4}{5}:\dfrac{4}{17}}{3\dfrac{2}{5}}\) \(\dfrac{\dfrac{28}{29}:\dfrac{4}{29}}{\dfrac{7}{9}:\dfrac{1}{9}}\) Cứu tui