a)

$3\frac{1}{2}=3\frac{50}{100}=3,5$

$\frac{7}{4}=1\frac{3}{4}=1\frac{75}{100}=1,75$

$\frac{9}{18}=\frac{50}{100}=0,5$

$\frac{27}{20}=1\frac{7}{20}=1\frac{35}{100}=1,35$ $\frac{27}{20}=1\frac{7}{20}=1\frac{35}{100}=1,35$

$\frac{3}{25}=\frac{12}{100}=0,12$

$1\frac{2}{5}=1\frac{4}{10}=1,4$

$\frac{126}{200}=\frac{630}{1000}=\frac{63}{100}=0,63$

$2\frac{105}{250}=2\frac{420}{1000}=2\frac{42}{100}=2,42$

$\frac{24}{15}=1\frac{9}{15}=1\frac{3}{5}=1\frac{6}{10}=1,6$

 

b)

$0,8=\frac{4}{5}$

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

$2,25=2\frac{1}{4}$

$0,3=\frac{3}{10}$

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

$5,08=5\frac{2}{25}$

$2,125=2\frac{1}{8}$

$21,5=21\frac{1}{2}$

$17,008=17\frac{1}{125}$