[tex]0,(3)\cdot0,1(6)=\frac{3}{9}\cdot\frac{16-1}{90}=\frac{1}{3}\cdot\frac{3}{18}=1/18;\\
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o,25\cdot\frac{4}{5}=\frac{1}{4}\cdot\frac{4}{5}=1/5 ;\\
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0,(13)\cdot\frac{10}{39}=\frac{13}{99}\cdot\frac{10}{39}=\frac{1}{99}\cdot\frac{10}{3}=\frac{10}{99\cdot3}=10/297 ;\\
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1,2(9)\cdot\frac{10}{3}=\frac{129-12}{90}\cdot\frac{10}{3}=\frac{117}{90}\cdot\frac{10}{3}=13/3;[/tex]