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![](https://rs.olm.vn/images/avt/0.png?1311)
\(\frac{1}{2}:\frac{3}{2}:\frac{5}{4}:\frac{6}{5}:\frac{7}{6}:\frac{8}{7}\)
\(=\frac{1}{2}\cdot\frac{2}{3}\cdot\frac{4}{5}\cdot\frac{5}{6}\cdot\frac{6}{7}\cdot\frac{7}{8}\)
\(=\frac{1\cdot\left(2\cdot5\cdot6\cdot7\right)}{8\cdot3\cdot\left(2\cdot5\cdot6\cdot7\right)}\)
\(=\frac{1}{24}\)
\(\frac{1}{2}\cdot\frac{2}{3}\cdot\frac{3}{4}\cdot\frac{4}{5}\cdot\frac{5}{6}\cdot\frac{6}{7}\cdot\frac{7}{8}\cdot\frac{8}{9}\cdot\frac{9}{10}\)
\(=\frac{1\cdot\left(2\cdot3\cdot4\cdot5\cdot6\cdot7\cdot8\cdot9\right)}{\left(2\cdot3\cdot4\cdot5\cdot6\cdot7\cdot8\cdot9\right)\cdot10}\)
\(=\frac{1}{10}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Bài 1 :
A = 1 - 1/2 + 1/2 - 1/4 + 1/4 - 1/8 + 1/8 - 1/16 + ... + 1/32 - 1/64
A = 1 - 1/64
A = 63/64
![](https://rs.olm.vn/images/avt/0.png?1311)
\(S=1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+\frac{1}{4}-\frac{1}{5}+\frac{1}{5}-\frac{1}{6}+\frac{1}{6}-\frac{1}{7}+\frac{1}{7}-\frac{1}{8}+\frac{1}{8}-\frac{1}{9}\)
\(S=1-\frac{1}{9}=\frac{8}{9}\)
![](https://rs.olm.vn/images/avt/0.png?1311)
Ta có: 272727x28 - 282828x27 = 27x10101x28 - 28x10101x27 = 0
Vậy, phép tính đã cho bằng 0
4) \(\frac{29x101-101}{2x19x101+4x101}\)
= \(\frac{\left(29-1\right)x101}{\left(38-4\right)x101}\)
=\(\frac{28}{34}=\frac{14}{17}\)
5) \(\left(\frac{2}{7}+\frac{11}{7}+\frac{1}{7}\right)-\frac{3}{8}-\frac{5}{8}+\frac{1}{3}\)
= \(\frac{14}{7}-\frac{8}{8}+\frac{1}{3}\)
= \(2-1+\frac{1}{3}=\frac{4}{3}\)
Nhớ tk cho mình nhé
1\(\frac{423133x846267+423134}{423133x846267+423134}=1\))
\(\frac{\left(423133+1\right)x846267-423133}{423133x846267+423134}\)
=\(\frac{423133x846267+846267-423133}{423133x846267+423134}\)
= \(\frac{423133x846267+423134}{423133x846267+423134}\)
= 1
Nhớ tk cho mình nhé (các câu sau làm riêng cho đỡ dài
![](https://rs.olm.vn/images/avt/0.png?1311)
d : \(\frac{8}{9}=\frac{8}{10}\)
d \(=\frac{8}{10}\)x \(\frac{8}{9}\)
d \(=\frac{32}{45}\)
ta có :
\(\frac{3}{7}=\frac{18}{42}\)
\(\frac{5}{6}=\frac{35}{42}\)
vì \(\frac{18}{42}< \frac{35}{42}\)
=> \(\frac{3}{7}< \frac{5}{6}\)
Ta có :
\(\frac{1}{5}:2\)= \(\frac{1}{5}\)x \(\frac{1}{2}\)= \(\frac{1}{10}\)
\(x+\frac{2}{5}=1-\frac{1}{6}\)
\(x+\frac{2}{5}=\frac{5}{6}\)
\(x=\frac{5}{6}-\frac{2}{5}=\frac{13}{30}\)
\(x=\frac{13}{30}\)
\(\frac{7}{8}-x=\frac{2}{3}+\frac{1}{8}\)
\(\frac{7}{8}-x=\frac{19}{24}\)
\(x=\frac{7}{8}-\frac{19}{24}=\frac{1}{12}\)
\(x=\frac{1}{12}\)