9/2

k mình nha

= \(\frac{9}{2}\)

ket qua bang 9/2

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

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

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

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

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

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

​

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 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!?

là dạng tính nhanh nhé !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!?

Mình làm luôn, koghi lại đề

A=\(\frac{5}{10}+\frac{5}{40}+\frac{5}{88}+\frac{5}{154}+\frac{5}{238}+\frac{5}{340}\)

A=\(\frac{5}{2.5}+\frac{5}{5.8}+\frac{5}{8.11}+\frac{5}{11.14}+\frac{5}{14.17}+\frac{5}{17.20}\)

A=\(\frac{5}{3}\left(\frac{1}{2}-\frac{1}{5}+\frac{1}{5}-\frac{1}{8}+...+\frac{1}{17}-\frac{1}{20}\right)\)

A=\(\frac{5}{3}.\left(\frac{1}{2}-\frac{1}{20}\right)\)

A=\(\frac{5}{3}.\frac{9}{20}\)

A=\(\frac{3}{4}\)

\(A=\frac{10}{1.2}+\frac{10}{2.3}+\frac{10}{3.4}+...+\frac{10}{98.99}+\frac{10}{99.100}\)

\(A=10.\left(\frac{1}{1.2}+\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{98.99}+\frac{1}{99.100}\right)\)

\(A=10.\left(\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{98}-\frac{1}{99}+\frac{1}{99}-\frac{1}{100}\right)\)

\(A=10.\left(\frac{1}{1}-\frac{1}{100}\right)\)

\(A=10.\frac{99}{100}\)

\(A=\frac{99}{10}\)

Học tốt 

a= \(10.\left(\frac{1}{1.2}+\frac{1}{2.3}+...+\frac{1}{99.100}\right)\)

a=\(10.\left(1-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{99}-\frac{1}{100}\right)\)

a=\(10.\left(1-\frac{1}{100}\right)\)

a=\(\frac{99}{10}\)

\(A=\frac{10}{1\cdot2}+\frac{10}{2\cdot3}+\frac{10}{3\cdot4}+...+\frac{10}{99\cdot100}\)

\(A=10\left(\frac{1}{1\cdot2}+\frac{1}{2\cdot3}+\frac{1}{3\cdot4}+...+\frac{1}{99\cdot100}\right)\)

\(A=10\left(1-\frac{1}{100}\right)\)

\(A=10\cdot\frac{99}{100}\)

\(A=\frac{99}{10}\)

\(=10.\left(\frac{1}{2.3}+\frac{1}{3.4}+\frac{1}{4.5}+...+\frac{1}{10.11}\right)\)

\(=10.\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+..+\frac{1}{10}-\frac{1}{11}\right)\)

\(=10\left(\frac{1}{2}-\frac{1}{11}\right)=10\cdot\frac{9}{22}=\frac{45}{11}\)

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

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

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

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

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

34/10 rút gọn được 17/5

k cho mk nha

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

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

Ta có : 

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

\(=\frac{7+8+9+10}{10}=\frac{34}{10}\)

Đap số : \(\frac{34}{10}\)

\(\simeq0.11\)