Uzupełnijmy zapisy.

a)
$3,75=3\frac{3}{4}=3\frac{6}{8}=\frac{30}{8}$

Ponieważ:

$0,75=\frac{75}{100}=\frac{3}{4}$

oraz

$3\frac{6}{8}=\frac{3\cdot 8+6}{8}=\frac{30}{8}$

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b)

$1\frac{1}{5}=1,2=\frac{12}{10}=\frac{120}{100}$

Ponieważ:

$0,2=\frac{2}{10}=\frac{1}{5}$

oraz

$1,2=\frac{12}{10}=\frac{120}{100}$

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c)

$\frac{12}{15}=\frac{4}{5}=\frac{8}{10}=\frac{80}{100}$

Ponieważ:

$\frac{4}{5}=\frac{4\cdot 3}{5\cdot 3}=\frac{12}{15}$

$\frac{4}{5}=\frac{4\cdot 2}{5\cdot 2}=\frac{8}{10}$

$\frac{4}{5}=\frac{4\cdot 20}{5\cdot 20}=\frac{80}{100}$

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d)

$\frac{104}{100}=1,04=1\frac{1}{25}=\frac{78}{75}$

Ponieważ:

$1,04=\frac{104}{100}$

oraz

$0,04=\frac{4}{100}=\frac{1}{25}$

czyli:

$1,04=1\frac{1}{25}=\frac{26}{25}=\frac{26\cdot 3}{25\cdot 3}=\frac{78}{75}$

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e)

$\frac{39}{12}=\frac{13}{4}=3\frac{1}{4}=3,25$

Ponieważ:

$\frac{39}{12}=\frac{39:3}{12:3}=\frac{13}{4}$

oraz

$\frac{13}{4}=3\frac{1}{4}=3,25$

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f)

$\frac{2125}{1000}=2,125=2\frac{1}{8}=\frac{17}{8}$

Ponieważ:

$2,125=\frac{2125}{1000}$

oraz

$0,125=\frac{125}{1000}=\frac{1}{8}$

więc:

$2\frac{1}{8}=\frac{2\cdot 8+1}{8}=\frac{17}{8}$