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1/90 : 0,25 + 1/90 : 0,2 + 1/90 : 125 - 1/90 : 0,1
= 1/90 x 4 + /90 x 5 + 1/90 x 8 : 1/90 x 10
= 1/90 x ( 4 + 5 + 8 + 10 )
= 1/90 x 27
= 3/10
\(\frac{1}{90}\) : 0,25 + \(\frac{1}{90}\) : 0,2 + \(\frac{1}{90}\) : 125 - \(\frac{1}{90}\) : 0,1
= \(\frac{1}{90}\) x 4 +\(\frac{1}{90}\) x 5 + x\(\frac{1}{90}\) 8 : \(\frac{1}{90}\) x 10
= \(\frac{1}{90}\) x ( 4 + 5 + 8 + 10 )
=\(\frac{1}{90}\) x 27
= \(\frac{3}{10}\)
hok tốt !
Em ơi chỗ 1/100 sửa lại thành 1/110 nha
B=\(\frac{1}{6}+\frac{1}{12}+\frac{1}{20}+...+\frac{1}{90}+\frac{1}{110}\)
=\(\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+\frac{1}{4\cdot5}+...+\frac{1}{9\cdot10}+\frac{1}{10\cdot11}\)(Dấu . là nhân nha)
Áp dugj tổng quát \(\frac{1}{x\left(x+1\right)}=\frac{1}{x}-\frac{1}{x+1}\)ta có:
B=\(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-...+\frac{1}{9}-\frac{1}{10}+\frac{1}{10}-\frac{1}{11}\)
=\(\frac{1}{2}-\frac{1}{11}\)=\(\frac{9}{22}\)
H=\(\left(1-\frac{1}{2}\right)\cdot\left(1-\frac{1}{3}\right)\cdot\cdot\cdot\left(1-\frac{1}{2004}\right)\)
=\(\frac{1}{2}\cdot\frac{2}{3}\cdot\frac{3}{4}\cdot\frac{4}{5}\cdot\frac{5}{6}\cdot\cdot\cdot\frac{2003}{2004}\)
=\(\frac{1}{2004}\)
(1000x0,1-900x0,1-90x0,1)x(142x0,5-240x0,25)
=cái gì đấy tự làm nhé !
\(25\frac{2}{13}-\left(\frac{15}{17}+15\frac{2}{3}\right)=\frac{327}{13}-\left(\frac{15}{17}+\frac{47}{3}\right)\)
\(=\frac{327}{13}-\frac{844}{51}\)
\(=\frac{5705}{663}\)
\(\frac{5}{30}+\frac{15}{90}+\frac{250}{150}+\frac{350}{210}+\frac{45}{270}=\frac{1}{6}+\frac{1}{6}+\frac{5}{3}+\frac{5}{3}+\frac{1}{6}\)
\(=\frac{3}{6}+\frac{10}{3}\)
\(=\frac{1}{2}+\frac{10}{3}\)
\(=\frac{23}{6}\)
\(3\frac{1}{11}.\frac{27}{46}.1\frac{6}{17}.2\frac{4}{9}=\frac{34}{11}.\frac{27}{46}.\frac{23}{17}.\frac{22}{9}\)
\(=\frac{68}{9}.\frac{27}{34}\)
\(=6\)