M = \(\dfrac{1}{1x2}+\dfrac{1}{2x3}+\dfrac{1}{3x4}+...+\dfrac{1}{99x100}\)

M = \(1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+...+\dfrac{1}{99}-\dfrac{1}{100}\)

M = \(1-\dfrac{1}{100}\)

M = \(\dfrac{99}{100}\)

\(M=1\times\dfrac{1}{2}+\dfrac{1}{2}\times\dfrac{1}{3}+\dfrac{1}{3}\times\dfrac{1}{4}+...+\dfrac{1}{99}\times\dfrac{1}{100}\)

\(M=1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+\dfrac{1}{3}-\dfrac{1}{4}+...+\dfrac{1}{99}-\dfrac{1}{100}\)

\(M=1-\dfrac{1}{100}\)

\(M=\dfrac{99}{100}\)

??????????

Ko bit làm 

\(=\frac{3}{2}\times\frac{4}{3}\times\frac{5}{4}\times...\times\frac{101}{100}=\frac{101}{2}\)

=3/2x4/3x5/4....x101/100

=3x4x5x...x101/2x3x4x...x100

=101/2

\(1\frac{1}{2}\times1\frac{1}{3}\times1\frac{1}{4}\times...\times1\frac{1}{100}\)

\(=\frac{3}{2}\times\frac{4}{3}\times\frac{5}{4}\times...\times\frac{101}{100}\)

\(=\frac{3\times4\times5\times...\times101}{2\times3\times4\times...\times100}\)

\(=\frac{101}{2}\)

(1-1/2) x (1-1/3) x .... x (1-1/100) 

= 1/2 x 2/3 x ... x 99/100 

= 1x2x...x99/2x3x..x100 

= 1/ 100 

a, \(\frac{3}{5}+25-\frac{1}{5}\)

\(=\left(\frac{3}{5}-\frac{1}{5}\right)+25\)

\(=\frac{2}{5}+25\)

\(=25\frac{2}{5}\)

\(=25,4\)

b, \(13.3.32,27+67,63.39\)

\(=39.32,27+67,63.39\)

\(=39\left(32,37+67,63\right)\)

\(=39.100\)

\(=3900\)

c, \(\left(1-\frac{1}{2}\right).\left(1-\frac{1}{3}\right).\left(1-\frac{1}{4}\right)....\left(1-\frac{1}{100}\right)\)

\(=\frac{1}{2}.\frac{2}{3}.\frac{3}{4}......\frac{99}{100}\)

\(=\frac{1}{100}\)

dấu chấm là gì hả bạn anna

Ta có:

\(\left(1-\frac{1}{3}\right)\left(1-\frac{1}{4}\right)\left(1-\frac{1}{5}\right)...\left(1-\frac{1}{100}\right)\)

\(=\left(\frac{3}{3}-\frac{1}{3}\right)\left(\frac{4}{4}-\frac{1}{4}\right)\left(\frac{5}{5}-\frac{1}{5}\right)...\left(\frac{100}{100}-\frac{1}{100}\right)\)

\(=\left(\frac{3-1}{3}\right)\left(\frac{4-1}{4}\right)\left(\frac{5-1}{5}\right)...\left(\frac{100-1}{100}\right)\)

\(=\frac{2}{3}.\frac{3}{4}.\frac{4}{5}...\frac{99}{100}\)

\(=\frac{2.3.4...99}{3.4.5...100}=\frac{2}{100}=\frac{1}{50}\)

Vậy \(\left(1-\frac{1}{3}\right)\left(1-\frac{1}{4}\right)\left(1-\frac{1}{5}\right)...\left(1-\frac{1}{100}\right)=\frac{1}{50}\)

bn ơi bn tìm trên google á

coá nhoa bn

a: \(=\dfrac{3}{2}\cdot\dfrac{4}{3}\cdot...\cdot\dfrac{2001}{2000}=\dfrac{2001}{2}\)

b: \(=101\left(34+13-27\right)=101\cdot20=2020\)

c: \(=24\%+8\%+59\%+9\%=1\)

a, = 1/2 x 2/3 x 3/4 x .... x 99/100 = 1/100

b, = 24/25 x 5/7 x 7/9 x .... x 97/99 = 24/25 x 5/99 = 8/165

a) \(\left(1-\frac{1}{2}\right)\cdot\left(1-\frac{1}{3}\right)\cdot\left(1-\frac{1}{4}\right)\cdot...\cdot\left(1-\frac{1}{100}\right)\)

=\(\frac{1}{2}\cdot\frac{2}{3}\cdot\frac{3}{4}\cdot...\cdot\frac{99}{100}\)

=