\(=\dfrac{29}{22}+\dfrac{41}{44}+\dfrac{33}{52}+\dfrac{73}{182}\)
\(=\dfrac{58+41}{44}+\dfrac{33}{52}+\dfrac{73}{182}\)
\(=\dfrac{9}{4}+\dfrac{33}{52}+\dfrac{73}{182}=\dfrac{23}{7}\)
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 = \(\left(\dfrac{1}{11}+\dfrac{1}{21}+\dfrac{1}{31}+\dfrac{1}{41}+\dfrac{1}{51}\right)\) \(\left(\dfrac{-41}{123}+\dfrac{31}{-186}-\dfrac{-51}{102}\right)\)
Tính nhanh:
\(A=\dfrac{5}{13}=\dfrac{-5}{7}+\dfrac{-20}{41}+\dfrac{8}{13}+\dfrac{-21}{41}\)
Tính tổng :
a) B = \(\dfrac{1}{5}\) + \(\dfrac{1}{20}\)+ \(\dfrac{1}{44}\) +\(\dfrac{1}{77}\) +\(\dfrac{1}{119}\) + \(\dfrac{1}{170}\) +\(\dfrac{1}{230}\) +\(\dfrac{1}{299}\)
b) C = \(\left(1+\dfrac{1}{1.3}\right)\) \(\left(1+\dfrac{1}{2.4}\right)\) \(\left(1+\dfrac{1}{3.5}\right)\) .....\(\left(1+\dfrac{1}{2014.2016}\right)\)
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=\(\dfrac{\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+...+\dfrac{1}{100}}{\dfrac{99}{1}+\dfrac{98}{2}+\dfrac{97}{3}+...+\dfrac{1}{99}}\)
Giúp mk với
Câu 1:
Cho A = \(\dfrac{1}{\dfrac{99}{\dfrac{1}{2}+}}+\dfrac{2}{\dfrac{98}{\dfrac{1}{3}+}}+\dfrac{3}{\dfrac{97}{\dfrac{1}{4}+....}}+...+\dfrac{99}{\dfrac{1}{\dfrac{1}{100}}}\).
B =\(\dfrac{92}{\dfrac{1}{45}+}-\dfrac{1}{\dfrac{9}{\dfrac{1}{50}+}}-\dfrac{2}{\dfrac{10}{\dfrac{1}{55}+}}-\dfrac{3}{\dfrac{11}{\dfrac{1}{60}+....}}-...\dfrac{92}{\dfrac{100}{\dfrac{1}{500}}}\). Tính \(\dfrac{A}{B}\)
rút gọn
\(\dfrac{\dfrac{1}{2}+\dfrac{1}{3}+\dfrac{1}{4}+...+\dfrac{1}{99}+\dfrac{1}{100}}{\dfrac{1}{99}+\dfrac{2}{98}+...+\dfrac{99}{1}}\)
Tính :
a, \(\dfrac{3\cdot13-13\cdot18}{15\cdot40-80}\);
b, \(\dfrac{18\cdot34+\left(-18\right)\cdot124}{-36\cdot17+9\cdot\left(-52\right)}\);
c, \(\dfrac{\dfrac{3}{41}-\dfrac{12}{47}+\dfrac{27}{53}}{\dfrac{4}{41}-\dfrac{16}{47}+\dfrac{36}{53}}+\dfrac{-0,25\cdot\dfrac{-2}{3}-0,75:\left(\dfrac{-1}{2}+\dfrac{2}{3}\right)}{\left|-1\dfrac{1}{2}\right|\cdot\left(\dfrac{-2}{3}-75\%:\dfrac{3}{-2}\right)}\).
Bài 4: so sánh biểu thức A và B
a) A=\(\dfrac{19}{41}+\dfrac{23}{53}+\dfrac{29}{61}\)
B=\(\dfrac{21}{41}+\dfrac{23}{49}+\dfrac{33}{65}\)
b) C=\(\dfrac{19^{20}+5}{19^{20}-8}vàD=\dfrac{19^{21}+6}{19^{21}-7}\)
Tính nhanh:
\(\dfrac{100}{1}.\dfrac{99}{2}.\dfrac{98}{3}.....\dfrac{-99}{200}.\dfrac{-100}{201}\)
Ai lm dc đảm bảo sẽ có GP
