a)

$\frac{5}{16}\cdot 3=\frac{5\cdot 3}{16}=\frac{15}{16}$  

 

$\frac{9}{10}\cdot 7=\frac{9\cdot 7}{10}=\frac{63}{10}=6\frac{3}{10}$  

 

$9\cdot 1\frac{2}{7}=9\cdot \frac{9}{7}=\frac{9\cdot 9}{7}=\frac{81}{7}=11\frac{4}{7}$  

 

$2\cdot 3\frac{7}{9}=2\cdot \frac{34}{9}=\frac{2\cdot 34}{9}=\frac{68}{9}=7\frac{5}{9}$  

 

$3\frac{2}{3}\cdot 5=\frac{11}{3}\cdot 5=\frac{11\cdot 5}{3}=\frac{55}{3}=11\frac{1}{3}$   

 

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b)     

$\sout{14}{}^2\cdot \frac{5}{\sout{21}{}_3}=\frac{2\cdot 5}{3}=\frac{10}{3}=3\frac{1}{3}$  

 

$\sout{18}{}^3\cdot \frac{7}{\sout{12}{}_2}=\frac{3\cdot 7}{2}=\frac{21}{2}=10\frac{1}{2}$   (w odpowiedziach z tyłu zbioru zadań jest pomyłka!)

 

$\sout{6}{}^2\cdot \frac{8}{\sout{9}{}_3}=\frac{2\cdot 8}{3}=\frac{16}{3}=5\frac{1}{3}$  

 

$\frac{7}{\sout{10}{}_2}\cdot \sout{15}{}^3=\frac{7\cdot 3}{2}=\frac{21}{2}=10\frac{1}{2}$  

 

$\frac{9}{\sout{16}{}_2}\cdot \sout{24}{}^3=\frac{9\cdot 3}{2}=\frac{27}{2}=13\frac{1}{2}$       

 

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c)

$2\frac{3}{4}\cdot 8=\frac{11}{\sout{4}{}_1}\cdot \sout{8}{}^2=11\cdot 2=22$  

 

$1\frac{5}{8}\cdot 6=\frac{13}{\sout{8}{}_4}\cdot \sout{6}{}^3=\frac{39}{4}=9\frac{3}{4}$   

 

$10\cdot 2\frac{1}{15}=\sout{10}{}^2\cdot \frac{31}{\sout{15}{}_3}=\frac{2\cdot 31}{3}=\frac{62}{3}=20\frac{2}{3}$  

 

$12\cdot 1\frac{1}{8}=\sout{12}{}^3\cdot \frac{9}{\sout{8}{}_2}=\frac{3\cdot 9}{2}=\frac{27}{2}=13\frac{1}{2}$  

 

$2\frac{5}{9}\cdot 6=\frac{23}{\sout{9}{}_3}\cdot \sout{6}{}^2=\frac{46}{3}=15\frac{1}{3}$