\(=\frac{1+2+3+4+5+6+7+8+9}{10}\)

\(=\frac{45}{10}=\frac{9}{2}\)

\(=\frac{45}{10}=\frac{9}{2}\)

a,

\(=\frac{1+2+3+4+5+6+7+8+9}{10}=\frac{45}{10}=\frac{9}{2}\)

b,\(=9\times\left(\frac{26\times10101}{27\times10101}+\frac{8\times11111}{9\times11111}\right)=9\times\left(\frac{26}{27}+\frac{8}{9}\right)=9\times\frac{50}{27}=\frac{50}{3}\)

k cho mk nha!!!!!!!!!!!!!

Mk cần gấp các bạn ơi !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!?

Đề bài là gì bạn ơi có chỗ ...

chưa có đề bạn ơi! Y_Y

Hok tốt ^_^

a) $\frac{1}{6}:\frac{3}{7} = \frac{1}{6} \times \frac{7}{3} = \frac{7}{{18}}$  

b) $\frac{5}{{12}}:\frac{1}{4} = \frac{5}{{12}} \times \frac{4}{1} = \frac{{5 \times 4}}{{12 \times 1}} = \frac{{5 \times 4}}{{4 \times 3 \times 1}} = \frac{5}{3}$

c) $\frac{4}{{15}}:\frac{8}{3} = \frac{4}{{15}} \times \frac{3}{8} = \frac{{4 \times 3}}{{15 \times 8}} = \frac{{4 \times 3}}{{5 \times 3 \times 4 \times 2}} = \frac{1}{{10}}$          

d) $\frac{{18}}{5}:\frac{9}{{10}} = \frac{{18}}{5} \times \frac{{10}}{9} = \frac{{18 \times 10}}{{5 \times 9}} = \frac{{9 \times 2 \times 5 \times 2}}{{5 \times 9}} = 4$

\(\frac{34}{10}\)

\(\frac{10}{10}+\frac{9}{10}+\frac{8}{10}+\frac{7}{10}\)

\(=\frac{10+9+8+7}{10}\)

\(=\frac{34}{10}\)

\(=\frac{17}{5}\)

\(=\frac{34}{10}\) minh minh lai

\(\frac{34}{10}=3,4\)

a ) \(\frac{9}{8}:\frac{3}{7}\)

= \(\frac{9}{7}X\frac{3}{8}\)

= 

A)  \(\frac{5}{8}+\frac{7}{6}\)

= 

a) $\frac{1}{6} + \frac{3}{2} + \frac{1}{2} = \frac{1}{6} + \left( {\frac{3}{2} + \frac{1}{2}} \right) = \frac{1}{6} + \frac{4}{2} = \frac{1}{6} + \frac{{12}}{6} = \frac{{13}}{6}$

b) $\frac{3}{8} + \frac{1}{2} + \frac{1}{8} = \left( {\frac{3}{8} + \frac{1}{8}} \right) + \frac{1}{2} = \frac{1}{2} + \frac{1}{2} = \frac{2}{2} = 1$

c) $\frac{2}{5} + \frac{6}{{10}} + \frac{3}{5} = \frac{2}{5} + \frac{3}{5} + \frac{3}{5} = \frac{{2 + 3 + 3}}{5} = \frac{8}{5}$

\(=\frac{9}{10}-\frac{7}{10}+\frac{7}{20}=\frac{2}{10}+\frac{7}{20}=\frac{4}{20}+\frac{7}{20}=\frac{11}{20}\)

\(\frac{9}{10}-\left(\frac{2}{5}+\frac{3}{10}\right)+\frac{7}{20}=\frac{9}{10}-\frac{7}{10}+\frac{7}{20}=\frac{2}{10}+\frac{7}{20}=\frac{4+7}{20}=\frac{11}{20}\)