Các câu hỏi tương tự
Cho S = \(\dfrac{6}{15}+\dfrac{6}{16}+\dfrac{6}{17}+\dfrac{6}{18}+\dfrac{6}{19}\) Chứng minh rằng 1<S<2
Bài 1.( 2 điểm)Tính bằng cách hợp lí:a) dfrac{1}{2}+dfrac{9}{10}+dfrac{5}{6}-dfrac{11}{14}-dfrac{1}{3}+dfrac{-4}{35}b) left(dfrac{18}{23}+dfrac{7}{12}right)+left(dfrac{-13}{19}-dfrac{3}{4}right)+left(dfrac{-6}{19}+dfrac{5}{23}right)c) dfrac{4}{3}+dfrac{-5}{6}+dfrac{-1}{4}d) dfrac{5}{6}-dfrac{7}{5}+dfrac{17}{30}
Đọc tiếp
Bài 1.( 2 điểm)Tính bằng cách hợp lí:
a) \(\dfrac{1}{2}+\dfrac{9}{10}+\dfrac{5}{6}-\dfrac{11}{14}-\dfrac{1}{3}+\dfrac{-4}{35}\)
b) \(\left(\dfrac{18}{23}+\dfrac{7}{12}\right)+\left(\dfrac{-13}{19}-\dfrac{3}{4}\right)+\left(\dfrac{-6}{19}+\dfrac{5}{23}\right)\)
c) \(\dfrac{4}{3}+\dfrac{-5}{6}+\dfrac{-1}{4}\)
d) \(\dfrac{5}{6}-\dfrac{7}{5}+\dfrac{17}{30}\)
1)\(\dfrac{1}{2}+\dfrac{13}{19}-\dfrac{4}{9}+\dfrac{6}{19}+\dfrac{5}{18}\)
2)\(\dfrac{ }{\dfrac{-20}{23}+\dfrac{2}{3}-\dfrac{3}{23}+\dfrac{2}{5}+\dfrac{7}{15}}\)
3)\(\dfrac{ }{\dfrac{4}{3}+\dfrac{-11}{31}+\dfrac{3}{10}-\dfrac{20}{31}-\dfrac{2}{5}}\)
4)\(\dfrac{ }{\dfrac{5}{7}.\dfrac{5}{11}+\dfrac{5}{7}.\dfrac{2}{11}-\dfrac{5}{7}.\dfrac{14}{11}}\)
25 tháng 1 2022 lúc 21:25
e) D = \(\dfrac{-5}{6}+\dfrac{-7}{12}-\dfrac{1}{3}\)
f) F = \(\dfrac{-3}{4}+\dfrac{1}{3}-\dfrac{-5}{18}\)
g) G = \(\dfrac{19}{9}-\dfrac{-4}{11}+\dfrac{2}{3}\)
h) H = \(\dfrac{5}{12}+\dfrac{-7}{4}-\dfrac{1}{-8}\)
11 tháng 5 2022 lúc 7:54
Chứng minh rằng:
\(\dfrac{1}{3^2}+\dfrac{1}{5^2}+\dfrac{1}{7^2}+...+\dfrac{1}{99^2}< \dfrac{5}{18}\)
B= \(\dfrac{1}{6}+\dfrac{1}{7}+\dfrac{1}{8}+...+\dfrac{1}{18}+\dfrac{1}{19}< 2\)
bài 3 thực hiện phép tínhadfrac{5}{8}+dfrac{3}{17}+dfrac{4}{18}+dfrac{20}{-17}+dfrac{-2}{9}+dfrac{21}{56}bleft(dfrac{9}{16}+dfrac{8}{-27}right)+left(1+dfrac{7}{16}+dfrac{-19}{27}right)cleft(dfrac{13}{5}+dfrac{7}{16}right)+left(dfrac{-15}{16}+dfrac{6}{15}right) d left(6-2dfrac{4}{5}right).3dfrac{1}{8}-1dfrac{3}{5}:dfrac{1}{4}
Đọc tiếp
bài 3 thực hiện phép tính
a\(\dfrac{5}{8}+\dfrac{3}{17}+\dfrac{4}{18}+\dfrac{20}{-17}+\dfrac{-2}{9}+\dfrac{21}{56}\)
b\(\left(\dfrac{9}{16}+\dfrac{8}{-27}\right)+\left(1+\dfrac{7}{16}+\dfrac{-19}{27}\right)\)
c\(\left(\dfrac{13}{5}+\dfrac{7}{16}\right)+\left(\dfrac{-15}{16}+\dfrac{6}{15}\right)\) d \(\left(6-2\dfrac{4}{5}\right).3\dfrac{1}{8}-1\dfrac{3}{5}:\dfrac{1}{4}\)
\(B=\dfrac{1}{6}+\dfrac{1}{7}+\dfrac{1}{8}+...+\dfrac{1}{18}+\dfrac{1}{19}\)
*Thực hiện1/ (dfrac{2021}{2020}+dfrac{2020}{2021}) x (dfrac{1}{2}-dfrac{1}{3}-dfrac{1}{6})2/ (dfrac{7}{19}-dfrac{5}{12}):dfrac{-5}{8}-(dfrac{7}{19}-dfrac{29}{12}):dfrac{5}{8}3/ dfrac{-5}{6}xdfrac{7}{24}-dfrac{5}{6}xdfrac{14}{24}-dfrac{5}{6}xdfrac{3}{24}
Đọc tiếp
*Thực hiện
1/ (\(\dfrac{2021}{2020}\)+\(\dfrac{2020}{2021}\)) x (\(\dfrac{1}{2}\)-\(\dfrac{1}{3}\)-\(\dfrac{1}{6}\))
2/ (\(\dfrac{7}{19}\)-\(\dfrac{5}{12}\)):\(\dfrac{-5}{8}\)-(\(\dfrac{7}{19}\)-\(\dfrac{29}{12}\)):\(\dfrac{5}{8}\)
3/ \(\dfrac{-5}{6}\)x\(\dfrac{7}{24}\)-\(\dfrac{5}{6}\)x\(\dfrac{14}{24}\)-\(\dfrac{5}{6}\)x\(\dfrac{3}{24}\)