Violympic toán 6
Các câu hỏi tương tự
Bài1. (4điểm) Thực hiện phép tính:
a) \(A=\dfrac{3}{5}+6\dfrac{5}{6}\left(11\dfrac{5}{20}-9\dfrac{1}{4}\right):8\dfrac{1}{3}\)
b) \(B=\dfrac{-1}{2}+\dfrac{-1}{6}+\dfrac{-1}{12}+\dfrac{-1}{20}+\dfrac{-1}{30}+\dfrac{-1}{42}+\dfrac{-1}{56}+\dfrac{-1}{72}+\dfrac{-1}{90}\)
Tính nhanh:
a) A 1 + dfrac{1}{5}+dfrac{1}{25}+dfrac{1}{125}+dfrac{1}{625}+...+dfrac{1}{78125}
b) B dfrac{1}{3}+dfrac{1}{12}+dfrac{1}{48}+dfrac{1}{192}+dfrac{1}{768}+...+dfrac{1}{36864}
c) M dfrac{1}{3}+dfrac{1}{6}+dfrac{1}{12}+dfrac{1}{20}+dfrac{1}{30}+...+dfrac{1}{9900}
d) P dfrac{1}{1+2}+dfrac{1}{1+2+3}+dfrac{1}{1+2+3+4}+...+dfrac{1}{1+2+3+4+...+2018}
Đọc tiếp
Tính nhanh:
a) A= 1 + \(\dfrac{1}{5}+\dfrac{1}{25}+\dfrac{1}{125}+\dfrac{1}{625}+...+\dfrac{1}{78125}\)
b) B= \(\dfrac{1}{3}+\dfrac{1}{12}+\dfrac{1}{48}+\dfrac{1}{192}+\dfrac{1}{768}+...+\dfrac{1}{36864}\)
c) M= \(\dfrac{1}{3}+\dfrac{1}{6}+\dfrac{1}{12}+\dfrac{1}{20}+\dfrac{1}{30}+...+\dfrac{1}{9900}\)
d) P= \(\dfrac{1}{1+2}+\dfrac{1}{1+2+3}+\dfrac{1}{1+2+3+4}+...+\dfrac{1}{1+2+3+4+...+2018}\)
\(\dfrac{\dfrac{3}{7}-\dfrac{3}{11}+\dfrac{3}{13}}{\dfrac{5}{7}-\dfrac{5}{11}+\dfrac{5}{13}}+\dfrac{\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{4}}{\dfrac{5}{4}-\dfrac{5}{6}+\dfrac{5}{8}}\)
THỰC HIỆN PHÉP TÍNH NHA MN
tính a, \(\dfrac{5.4^{15}.9^9-4.30^{20}8^9}{5.2^9.6^{19}-7.2^{29}.27^6}\)
b, 1\(\dfrac{1}{30}\):\(\left(24\dfrac{1}{6}-24\dfrac{1}{5}\right)-\dfrac{1\dfrac{1}{2}-\dfrac{3}{4}}{4x-\dfrac{1}{2}}=\left(-1\dfrac{1}{15}\right):\left(8\dfrac{1}{5}-8\dfrac{1}{3}\right)\)
1/ Cho S dfrac{1}{11} + dfrac{1}{12} + dfrac{1}{13} + ... + dfrac{1}{19} + dfrac{1}{20}
So sánh S với dfrac{1}{2}
2/ Tìm x biết: dfrac{x}{12} dfrac{-1}{24}- dfrac{1}{8}
3/Tính 1 cách hợp lí: dfrac{2}{5.7}+ dfrac{2}{7.9}+ ...+ dfrac{2}{19.21}
GIÚP MK VS!!! MK ĐG GẤP LẮM . MƠN M.N NHÌU Ạ!
Đọc tiếp
1/ Cho S= \(\dfrac{1}{11} + \dfrac{1}{12} + \dfrac{1}{13} + ... + \dfrac{1}{19} + \dfrac{1}{20}\)
So sánh S với \(\dfrac{1}{2}\)
2/ Tìm x biết: \(\dfrac{x}{12}= \dfrac{-1}{24}- \dfrac{1}{8}\)
3/Tính 1 cách hợp lí: \(\dfrac{2}{5.7}+ \dfrac{2}{7.9}+ ...+ \dfrac{2}{19.21}\)
GIÚP MK VS!!! MK ĐG GẤP LẮM >.< MƠN M.N NHÌU Ạ!
DX
4 tháng 2 2021 lúc 12:31
a) Tính A ( 1 - dfrac{1}{2} )( 1 - dfrac{1}{3} ) (1-dfrac{1}{4} ) ....(1-dfrac{1}{2014} ) (1-dfrac{1}{2015} ) (1-dfrac{1}{2016} )b)Tìm x biết dfrac{x-2}{12} + dfrac{x-2}{20} + dfrac{x-2}{30}+ dfrac{x-2}{42} + dfrac{x-2}{56} +dfrac{x-2}{72} dfrac{16}{9}
Đọc tiếp
a) Tính A = ( 1 - \(\dfrac{1}{2}\) )( 1 - \(\dfrac{1}{3}\) ) (1-\(\dfrac{1}{4}\) ) ....(1-\(\dfrac{1}{2014}\) ) (1-\(\dfrac{1}{2015}\) ) (1-\(\dfrac{1}{2016}\) )
b)Tìm x biết \(\dfrac{x-2}{12}\) + \(\dfrac{x-2}{20}\) + \(\dfrac{x-2}{30}\)+ \(\dfrac{x-2}{42}\) + \(\dfrac{x-2}{56}\) +\(\dfrac{x-2}{72}\) = \(\dfrac{16}{9}\)
Bài 1: Tính tổng 100 số hạng đầu tiên của các dãy sau:
a)dfrac{1}{2};dfrac{1}{6};dfrac{1}{12};dfrac{1}{20};dfrac{1}{30};...
b)dfrac{1}{6};dfrac{1}{66};dfrac{1}{176};dfrac{1}{336};...
Bài 2: Tính:
a)Adfrac{1+dfrac{1}{3}+dfrac{1}{5}+...+dfrac{1}{97}+dfrac{1}{99}}{dfrac{1}{1.99}+dfrac{1}{3.97}+dfrac{1}{5.95}+...+dfrac{1}{97.3}+dfrac{1}{99.1}}
b)Bdfrac{dfrac{1}{2}+dfrac{1}{3}+dfrac{1}{4}+...+dfrac{1}{100}}{dfrac{99}{1}+dfrac{98}{2}+dfrac{97}{3}+...+dfrac{1}{99}}
Đọc tiếp
Bài 1: Tính tổng 100 số hạng đầu tiên của các dãy sau:
a)\(\dfrac{1}{2};\dfrac{1}{6};\dfrac{1}{12};\dfrac{1}{20};\dfrac{1}{30};...\)
b)\(\dfrac{1}{6};\dfrac{1}{66};\dfrac{1}{176};\dfrac{1}{336};...\)
Bài 2: Tính:
a)A=\(\dfrac{1+\dfrac{1}{3}+\dfrac{1}{5}+...+\dfrac{1}{97}+\dfrac{1}{99}}{\dfrac{1}{1.99}+\dfrac{1}{3.97}+\dfrac{1}{5.95}+...+\dfrac{1}{97.3}+\dfrac{1}{99.1}}\)
b)B=\(\dfrac{\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+...+\dfrac{1}{100}}{\dfrac{99}{1}+\dfrac{98}{2}+\dfrac{97}{3}+...+\dfrac{1}{99}}\)
DX
23 tháng 2 2021 lúc 9:15
Tìm x :
a) \(\left|x+\dfrac{11}{17}\right|+\left|x+\dfrac{2}{17}\right|+\left|x+\dfrac{4}{17}\right|=4x\)
b) \(\left|x+\dfrac{1}{2}\right|+\left|x+\dfrac{1}{6}\right|+\left|x+\dfrac{1}{12}\right|+\left|x+\dfrac{1}{20}\right|+..+\left|x+\dfrac{1}{110}\right|=11x\)
CMR : \(\dfrac{2}{5}< A< \dfrac{8}{9}\)
Với \(A=\dfrac{1}{2^2}+\dfrac{1}{3^2}+\dfrac{1}{4^2}+\dfrac{1}{5^2}+\dfrac{1}{6^2}+\dfrac{1}{7^2}+\dfrac{1}{8^2}+\dfrac{1}{9^2}\)