Lời giải:
$=\frac{39}{154}+\frac{55}{19}=\frac{9211}{2926}$
Lời giải:
$=\frac{39}{154}+\frac{55}{19}=\frac{9211}{2926}$
\(\dfrac{21}{24}\)x\(\dfrac{2}{11}\):\(\dfrac{9}{8}\)=.......
\(\dfrac{17}{9}\)x\(\dfrac{5}{6}\):\(\dfrac{12}{13}\)=.......
Tính bằng cách thuận tiện nhất
\(\dfrac{13}{18}\) x \(\dfrac{9}{26}\) x \(\dfrac{2}{3}\) =
\(\dfrac{44}{15}\) x \(\dfrac{5}{22}\) x \(\dfrac{3}{2}\) =
\(A=\dfrac{1}{15}+\dfrac{1}{35}+\dfrac{1}{65}+...+\dfrac{1}{99}=\dfrac{16}{x}\)
\(B=\dfrac{5}{6}+\dfrac{11}{12}+\dfrac{19}{20}+\dfrac{29}{30}+\dfrac{41}{42}+\dfrac{55}{56}+\dfrac{x}{16}\)\(C=\left(1-\dfrac{1}{4}\right)\times\left(1-\dfrac{1}{9}\right)\times\left(1-\dfrac{1}{16}\right)\times...\times\left(1-\dfrac{1}{100}\right)=\dfrac{22}{x}\)
m.ng giúp em với
bài 2: kết quả phép tính \(\dfrac{7}{19}\) x \(\dfrac{1}{3}\) + \(\dfrac{7}{19}\) x \(\dfrac{2}{3}\)=
a. \(\dfrac{14}{21}\)
b.\(\dfrac{21}{19}\)
c.\(\dfrac{14}{57}\)
d.\(\dfrac{7}{19}\)
Tính nhanh:
a)A=\(\dfrac{4026x2014+4030}{2013x2016-2011}\)
b)\(\dfrac{5x12+10x9-100}{\dfrac{1}{5}x\left(9+11+13+10+17+19+21\right)}\)
\(\dfrac{1}{1\times2}+\dfrac{1}{2\times3}+\dfrac{1}{3\times4}+\dfrac{1}{4\times5}+...+\dfrac{1}{98\times99}+\dfrac{1}{99\times100}\)
\(\dfrac{2}{11\times13}+\dfrac{2}{13\times15}+...+\dfrac{2}{19\times21}+\dfrac{2}{21\times23}\)
A = \(\dfrac{28}{25}\) + \(\dfrac{9}{10}\) - \(\dfrac{11}{15}\) + \(\dfrac{13}{21}\) - \(\dfrac{15}{28}\) + \(\dfrac{17}{26}\) - ... + \(\dfrac{197}{4851}\) - \(\dfrac{199}{4950}\)
Tính bằng cách thuận tiện
\(^{\dfrac{21}{11}}\) x \(\dfrac{22}{17}\) x \(\dfrac{68}{63}\)
Tính nhanh:
\(\dfrac{17}{13}:\dfrac{51}{26}=\dfrac{17}{13}x\dfrac{26}{51}=\dfrac{17x13x2}{13x17x3}=\dfrac{2}{3}\)
\(\dfrac{33}{38}:\dfrac{11}{19}\)=?