Violympic toán 6
Các câu hỏi tương tự
\(B=\left(\dfrac{0,4-\dfrac{2}{9}+\dfrac{2}{11}}{1,4-\dfrac{7}{9}+\dfrac{7}{11}}-\dfrac{\dfrac{1}{3}-0,25+\dfrac{1}{5}}{1^1_6-0,875+0,7}\right).\dfrac{1842009}{1842010}\)
Tính giá trị của biểu thức
A=\(\dfrac{\dfrac{5}{12}+\dfrac{3}{4}-1}{3-\dfrac{5}{6}+\dfrac{2}{3}}\)+\(\dfrac{\dfrac{16}{5}+\dfrac{16}{7}-\dfrac{16}{9}}{\dfrac{17}{5}+\dfrac{17}{7}-\dfrac{17}{9}}\)
Chứng minh :
A =\(\dfrac{1}{2}+\dfrac{1}{33}+\dfrac{1}{34}+\dfrac{1}{35}+\dfrac{1}{51}+\dfrac{1}{53}+\dfrac{1}{55}+\dfrac{1}{57}+\dfrac{1}{59}\)<\(\dfrac{7}{10}\)
\(\dfrac{10}{17}+\dfrac{9}{16}+\dfrac{11}{34}>\dfrac{1}{2}CMR\) 
Các bạn giúp với :Bài 1:a, CMR: A dfrac{3}{1^2.2^2}+dfrac{5}{2^2.3^2}+dfrac{7}{3^2.4^2}+...+dfrac{21}{10^2.11^2} 1b, Cho B dfrac{3}{4}+dfrac{8}{9}+dfrac{15}{16}+dfrac{24}{25}+...+dfrac{2499}{2500}. CMR: B không phải là số nguyên.c, So sánh: C dfrac{2}{2^1}+dfrac{3}{2^2}+dfrac{4}{2^3}+...+dfrac{2021}{2^{2020}} với 3.
Đọc tiếp
Các bạn giúp với :<
Bài 1:
a, CMR: A = \(\dfrac{3}{1^2.2^2}+\dfrac{5}{2^2.3^2}+\dfrac{7}{3^2.4^2}+...+\dfrac{21}{10^2.11^2}< 1\)
b, Cho B = \(\dfrac{3}{4}+\dfrac{8}{9}+\dfrac{15}{16}+\dfrac{24}{25}+...+\dfrac{2499}{2500}.\) CMR: B không phải là số nguyên.
c, So sánh: C = \(\dfrac{2}{2^1}+\dfrac{3}{2^2}+\dfrac{4}{2^3}+...+\dfrac{2021}{2^{2020}}\) với 3.
2. tìm x
a. dfrac{x}{8}dfrac{-9}{6}
b. dfrac{4}{9}+dfrac{7}{3}:xdfrac{1}{5}
c. dfrac{-5}{9}- xdfrac{4}{3}
d. x +dfrac{4}{17}dfrac{2}{34}
e. dfrac{3}{4}.xdfrac{7}{8}
f. 5dfrac{4}{7}: x11
Đọc tiếp
2. tìm x
a. \(\dfrac{x}{8}\)=\(\dfrac{-9}{6}\)
b. \(\dfrac{4}{9}\)+\(\dfrac{7}{3}\):x=\(\dfrac{1}{5}\)
c. \(\dfrac{-5}{9}\)- x=\(\dfrac{4}{3}\)
d. x +\(\dfrac{4}{17}\)=\(\dfrac{2}{34}\)
e. \(\dfrac{3}{4}\).x=\(\dfrac{7}{8}\)
f. \(5\dfrac{4}{7}\): x=11
1. tính
a. dfrac{3}{5}-dfrac{2}{3}+dfrac{16}{15}
b. (dfrac{5}{6}-dfrac{4}{5}):dfrac{7}{30}-dfrac{6}{7}
c. dfrac{4}{11}.dfrac{-2}{9}+dfrac{4}{11}.dfrac{-8}{9}+dfrac{4}{11}.dfrac{1}{9}
d.dfrac{-13}{10}-dfrac{15}{16}:dfrac{-3}{4}+dfrac{21}{25}.dfrac{-15}{28}
Đọc tiếp
1. tính
a. \(\dfrac{3}{5}\)-\(\dfrac{2}{3}\)+\(\dfrac{16}{15}\)
b. (\(\dfrac{5}{6}\)-\(\dfrac{4}{5}\)):\(\dfrac{7}{30}\)-\(\dfrac{6}{7}\)
c. \(\dfrac{4}{11}\).\(\dfrac{-2}{9}\)+\(\dfrac{4}{11}\).\(\dfrac{-8}{9}\)+\(\dfrac{4}{11}\).\(\dfrac{1}{9}\)
d.\(\dfrac{-13}{10}\)-\(\dfrac{15}{16}\):\(\dfrac{-3}{4}\)+\(\dfrac{21}{25}\).\(\dfrac{-15}{28}\)
Thực hiện phép tính một cách hợp lý :
a) dfrac{-12}{7} . dfrac{4}{35} + dfrac{12}{7} . dfrac{-31}{35} - dfrac{2}{7}
b) 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + ... + 97 + 98 - 99 - 100.
c) A 157 . ( - 37 ) - ( 41 . 53 - 37 . 157 ) + 51 . 53
d) B left(dfrac{1}{11}+dfrac{1}{21}+dfrac{1}{31}+dfrac{1}{41}+dfrac{1}{51}right) left(dfrac{-41}{123}+dfrac{31}{-186}-dfrac{-51}{102}right)
Đọc tiếp
Thực hiện phép tính một cách hợp lý :
a) \(\dfrac{-12}{7}\) . \(\dfrac{4}{35}\) + \(\dfrac{12}{7}\) . \(\dfrac{-31}{35}\) - \(\dfrac{2}{7}\)
b) 1 + 2 - 3 - 4 + 5 + 6 - 7 - 8 + ... + 97 + 98 - 99 - 100.
c) A = 157 . ( - 37 ) - ( 41 . 53 - 37 . 157 ) + 51 . 53
d) B = \(\left(\dfrac{1}{11}+\dfrac{1}{21}+\dfrac{1}{31}+\dfrac{1}{41}+\dfrac{1}{51}\right)\) \(\left(\dfrac{-41}{123}+\dfrac{31}{-186}-\dfrac{-51}{102}\right)\)
\(\dfrac{5}{9}\).\(\dfrac{2}{7}\)+\(\dfrac{5}{9}\).\(\dfrac{5}{7}\) - \(\dfrac{8}{3}\)