Ta có:A=20,13.100+2013.100/50+201,3:0,1+2,013:0,001

        A=2013+2013.2+2013+2013

        A=2013.(1+2+1+1)

        A=2013.5

        A=10065

Ta có:A=20,13.100+2013.100/50+201,3:0,1+2,013:0,001

           A=2013+2013.2+2013+2013

           A=2013.(1+2+1+1)

           A=2013.5

           A=10065

= 2013

Ta có: 

\(A=\frac{1^2}{1.2}.\frac{2^2}{2.3}.\frac{3^2}{3.4}...\frac{99^2}{99.100}.\frac{100^2}{100.101}\)

\(=\frac{1}{2}.\frac{4}{6}.\frac{9}{12}....\frac{9801}{9900}.\frac{10000}{10100}\)

\(=\frac{1}{2}.\frac{2}{3}.\frac{3}{4}...\frac{99}{100}.\frac{100}{101}=\frac{1.2.3...99.100}{2.3.4...100.101}=\frac{1}{101}\)(Tối giản)

\(\frac{19,01\div0,1\times\left(208\times9+208\right)}{2,08\times100\div0,01}\)

\(=\frac{190,1\times\left(208\times9+208\times1\right)}{208\div0,01}\)

\(=\frac{190,1\times\left[208\times\left(9+1\right)\right]}{20800}\)

\(=\frac{190,1\times\left[208\times10\right]}{20800}\)

\(=\frac{190,1\times2080}{20800}\)

\(=\frac{190,1\times10\times208}{100\times208}\)

\(=\frac{1901}{100}\)

\(\frac{19,01\div0,1\times(208\times9+208)}{2,08\times100\div0,01}\)

\(=\frac{19,01\div\frac{1}{10}\times(208\times9+208\times1)}{208\div\frac{1}{100}}\)

\(=\frac{19,01\times10\times\left[208\times(9+1)\right]}{208\times100}\)

\(=\frac{19,01\times100\times208\times10}{208\times100}=19,01\times10=190,1\)