\(\dfrac{\dfrac{1}{6}-\dfrac{1}{39}+\dfrac{1}{51}}{\dfrac{1}{8}-\dfrac{1}{52}+\dfrac{1}{68}}\)
\(\dfrac{11}{\dfrac{78}{\dfrac{11}{104}+\dfrac{1}{68}}}+\dfrac{1}{51}\)
\(\dfrac{71}{\dfrac{442}{\dfrac{213}{1768}}}\)\(\Rightarrow\dfrac{4}{3}\)
Bài 1: Thực hiện phép tính:
a) A = [6.(\(\dfrac{1}{3}\))3- 3 (-\(\dfrac{1}{3}\))+ 1 ] : (-\(\dfrac{1}{3}\)-1)
b) B = \(\dfrac{\dfrac{1}{39}-\dfrac{1}{6}-\dfrac{1}{51}}{\dfrac{1}{8}-\dfrac{1}{52}+\dfrac{1}{68}}:5\dfrac{1}{6}\)
Tính \(P=\dfrac{\dfrac{1}{51}+\dfrac{1}{52}+...+\dfrac{1}{100}}{\dfrac{1}{1.2}+\dfrac{1}{3.4}+...+\dfrac{1}{99.100}}\)
2. thực hiện phép tính
a. \(\dfrac{3}{8}.72\dfrac{1}{5}-51\dfrac{1}{5}.\dfrac{3}{8}\)
b.\(25.\left(\dfrac{-1}{5}^{ }\right)^3+\dfrac{1}{5}-2.\left(\dfrac{-1}{2}\right)^2-\dfrac{1}{2}\)
c.\(35\dfrac{1}{6}.\dfrac{-4}{5}-45\dfrac{1}{6}.\dfrac{-1}{5}\)
\(2+\dfrac{1}{2+\dfrac{1}{1+\dfrac{68}{288}}}\)
\(2+\dfrac{1}{2+\dfrac{1}{1+\dfrac{68}{288}}}\)
\(2+\dfrac{1}{2+\dfrac{1}{1+\dfrac{68}{288}}}\)
\(tính:\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{4}-\dfrac{1}{5}+\dfrac{1}{6}-\dfrac{1}{7}+\dfrac{1}{8}+\dfrac{1}{7}-\dfrac{1}{6}+\dfrac{1}{5}-\dfrac{1}{4}+\dfrac{1}{3}-\dfrac{1}{2}\)
8) \(A=\dfrac{9}{10}-\dfrac{1}{90}-\dfrac{1}{72}-\dfrac{1}{56}-\dfrac{1}{42}-\dfrac{1}{30}-\dfrac{1}{20}-\dfrac{1}{12}-\dfrac{1}{6}-\dfrac{1}{2}\)
9) \(B=\dfrac{1}{3}+\dfrac{1}{3^2}+\dfrac{1}{3^4}+...+\dfrac{1}{3^{2014}}+\dfrac{1}{3^{2015}}\)
10) \(P=\dfrac{\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+...+\dfrac{1}{2005}}{\dfrac{2004}{1}+\dfrac{2003}{2}+\dfrac{2002}{3}+...+\dfrac{1}{2004}}\)
Thực hiện phép tính một cách hợp lí
a) 0,5+\(\dfrac{1}{3}+0,4+\dfrac{5}{7}+\dfrac{1}{6}-\dfrac{4}{35}\)
b)\(\dfrac{8}{9}-\dfrac{1}{72}-\dfrac{1}{56}-\dfrac{1}{42}-\dfrac{1}{30}-\dfrac{1}{20}-\dfrac{1}{12}-\dfrac{1}{6}-\dfrac{1}{2}\)
câu 1 . tìm x
a. \(x:3\dfrac{1}{15}=1\dfrac{1}{2}\)
b.\(x.\dfrac{3}{2}=\dfrac{-7}{6}\)
c. \(\dfrac{5}{6}+\dfrac{1}{4}:x=\dfrac{-2}{3}\)
d. \(\dfrac{-2}{13}.x=\dfrac{-9}{26}\)
e. \(\dfrac{1}{2}.x-\dfrac{1}{10}=\dfrac{2}{3}\)
f.\(-52+\dfrac{2}{3}.x=-46\)
A=\(\dfrac{\dfrac{3}{4}-\dfrac{3}{11}+\dfrac{3}{13}}{\dfrac{5}{7}-\dfrac{5}{11}+\dfrac{5}{13}}+\dfrac{\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{4}}{\dfrac{5}{4}-\dfrac{5}{6}+\dfrac{5}{8}}\)
