5/10-4/25; 45/100-17/50; 75/100-1/5; 2/5-15/100

[latex] \frac{5}{10} - \frac{4}{25} = \frac{5*10}{10*10} - \frac{4*4}{25*4} = \frac{50}{100} - \frac{16}{100} = \frac{50-16}{100} = \frac{34}{100} =0,34[/latex] [latex] \frac{45}{100} - \frac{17}{50} = \frac{45}{100} - \frac{34}{100}= \frac{11}{100} =0,11[/latex] [latex] \frac{75}{100} - \frac{1}{5} = \frac{75}{100} - \frac{20}{100} = \frac{55}{100} =0,55[/latex] [latex] \frac{2}{5} - \frac{15}{100} = \frac{40}{100} - \frac{15}{100} = \frac{25}{100} =0,25[/latex]

5/10-4/25=17/50; 45/100-17/50=11/100; 75/100-1/5=11/20; 2/5-15/100=1/4.