Wykonajmy obliczenia:

$2\frac{2}{5}+2\frac{7}{20}=2\frac{8}{20}+2\frac{7}{20}=4\frac{15}{20}=4\frac{3}{4}$  

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$5\frac{1}{3}-3\frac{8}{15}=5\frac{5}{15}-3\frac{8}{15}=4\frac{20}{15}-3\frac{8}{15}=1\frac{12}{15}=1\frac{4}{5}$  

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$4\frac{1}{2}-1\frac{2}{3}=4\frac{3}{6}-1\frac{4}{6}=3\frac{9}{6}-1\frac{4}{6}=2\frac{5}{6}$  

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$8\frac{2}{3}\cdot \frac{3}{14}=\frac{26}{\cancel{3}{}_1}\cdot \frac{\cancel{3}{}^1}{14}=\frac{26}{14}=\frac{13}{7}=1\frac{6}{7}$  

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$\frac{15}{16}\cdot 5\frac{1}{5}=\frac{\cancel{15}{}^3}{16}\cdot \frac{26}{\cancel{5}{}_1}=\frac{78}{16}=\frac{39}{8}=4\frac{7}{8}$  

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$2\frac{2}{3}:\frac{12}{13}=\frac{\cancel{8}{}^2}{3}\cdot \frac{13}{\cancel{12}{}_3}=\frac{26}{9}=2\frac{8}{9}$  

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$5\frac{1}{4}:1\frac{1}{14}=\frac{21}{4}:\frac{15}{14}=\frac{\cancel{21}{}^7}{4}\cdot \frac{14}{\cancel{15}{}_5}=\frac{7}{\cancel{4}{}_2}\cdot \frac{\cancel{14}{}^7}{5}=\frac{49}{10}=4\frac{9}{10}$  

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Uzupełnijmy okienka: