Đại số lớp 6
Các câu hỏi tương tự
\(\dfrac{1}{51}+\dfrac{1}{52}+\dfrac{1}{53}+...+\dfrac{1}{100}:\dfrac{1}{1.2}+\dfrac{1}{2.3}+...+\dfrac{1}{99.100}\)
\(\dfrac{1}{51}+\dfrac{1}{52}+\dfrac{1}{53}+...+\dfrac{1}{100}:\dfrac{1}{1-2}+\dfrac{1}{2-3}+...+\dfrac{1}{99-100}\)
Chứng minh :
\(\dfrac{1}{2}\) < \(\dfrac{1}{51}+\dfrac{1}{52}+\dfrac{1}{53}+....+\dfrac{1}{100}\) < 1
Bài 1: Cho A=\(\dfrac{1}{1.2}+\dfrac{1}{3.4}+\dfrac{1}{5.6}+...+\dfrac{1}{99.100}\)
a) Chứng minh: A=\(\dfrac{1}{51}+\dfrac{1}{52}+\dfrac{1}{53}+...+\dfrac{1}{100}\)
b) Chứng minh: A<\(\dfrac{5}{6}\)
Tính nhanh:
B(dfrac{1}{51}+dfrac{1}{52}+dfrac{1}{53}+....+dfrac{1}{100}):(dfrac{1}{1.2}+dfrac{1}{2.3}+dfrac{1}{3.4}+...+dfrac{1}{99.100})
giúp với ạ
Đọc tiếp
Tính nhanh:
B=(\(\dfrac{1}{51}\)+\(\dfrac{1}{52}\)+\(\dfrac{1}{53}\)+....+\(\dfrac{1}{100}\)):(\(\dfrac{1}{1.2}\)+\(\dfrac{1}{2.3}\)+\(\dfrac{1}{3.4}\)+...+\(\dfrac{1}{99.100}\))
giúp với ạ 
Tính nhanh
a)(5dfrac{1}{7}- 3dfrac{3}{11}) - 2dfrac{1}{7}-1dfrac{8}{11}
b) (dfrac{1999}{2011}-dfrac{2011}{1999}) -(dfrac{-12}{1999}-dfrac{12}{2011})
c)(1-dfrac{1}{2})(1-dfrac{1}{3})............(1-dfrac{1}{2017})
d) dfrac{2}{15}.6dfrac{5}{11}+dfrac{5}{11}.dfrac{-2}{15}-dfrac{2}{15}.2015^0
e)dfrac{1}{6}-dfrac{1}{39}+dfrac{1}{51}:dfrac{1}{8}-dfrac{1}{12}+dfrac{1}{68}
Đọc tiếp
Tính nhanh
a)(5\(\dfrac{1}{7}\)- 3\(\dfrac{3}{11}\)) - 2\(\dfrac{1}{7}\)-1\(\dfrac{8}{11}\)
b) (\(\dfrac{1999}{2011}-\dfrac{2011}{1999}\)) -(\(\dfrac{-12}{1999}-\dfrac{12}{2011}\))
c)(1-\(\dfrac{1}{2}\))(1-\(\dfrac{1}{3}\))............(1-\(\dfrac{1}{2017}\))
d) \(\dfrac{2}{15}.6\dfrac{5}{11}+\dfrac{5}{11}.\dfrac{-2}{15}\)\(-\dfrac{2}{15}.2015^0\)
e)\(\dfrac{1}{6}-\dfrac{1}{39}+\dfrac{1}{51}\):\(\dfrac{1}{8}-\dfrac{1}{12}+\dfrac{1}{68}\)
BT2: Tính nhanh:
1) \(\dfrac{15}{37}\left(\dfrac{38}{41}-\dfrac{74}{45}\right)-\dfrac{38}{41}\left(\dfrac{15}{37}+\dfrac{82}{76}\right)\)
2)\(\dfrac{47}{53}\left(\dfrac{17}{3}-\dfrac{53}{47}\right)+\dfrac{17}{3}\left(\dfrac{6}{17}-\dfrac{47}{53}\right)\)
BT2: Tính nhanh:
9)\(\dfrac{47}{51}\left(\dfrac{17}{94}-\dfrac{53}{91}\right)-\dfrac{53}{91}\left(\dfrac{91}{53}-\dfrac{47}{51}\right)\)
10)\(\dfrac{13}{19}\left(\dfrac{19}{26}-\dfrac{71}{43}\right)+\dfrac{71}{43}\left(\dfrac{13}{19}-\dfrac{86}{71}\right)\)
Tính \(H=\dfrac{\dfrac{1}{99}+\dfrac{2}{98}+\dfrac{3}{97}+...........+\dfrac{99}{1}}{\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+.............+\dfrac{1}{100}}:\dfrac{92-\dfrac{1}{9}-\dfrac{1}{10}-..............\dfrac{92}{100}}{\dfrac{1}{45}+\dfrac{1}{50}+\dfrac{1}{55}+........+\dfrac{1}{500}}\)
Help me!!!