Odpowiedź:
[tex]\huge\boxed{\boxed{a)=1\frac{1}{12}}}[/tex]
[tex]\huge\boxed{\boxed{b)=7\frac{7}{30}}}[/tex]
[tex]\huge\boxed{\boxed{c)=3\frac{2}{15}}}[/tex]
Szczegółowe wyjaśnienie:
[tex]\frac{1}{2}+\frac{1}{3}+\frac{1}{4}=\frac{1\cdot6}{2\cdot6}+\frac{1\cdot4}{3\cdot4}+\frac{1\cdot3}{4\cdot3}=\frac{6}{12}+\frac{4}{12}+\frac{3}{12}=\frac{13}{12}=1\frac{1}{12}\\\\1\frac{2}{5}+3\frac{1}{3}+2\frac{1}{2}=1\frac{2\cdot6}{5\cdot6}+3\frac{1\cdot10}{3\cdot10}+2\frac{1\cdot15}{2\cdot15}=1\frac{12}{30}+3\frac{10}{30}+2\frac{15}{30}=6\frac{37}{30}=7\frac{7}{30}[/tex]
[tex]4\frac{1}{3}-2\frac{2}{5}+1\frac{1}{5}=4\frac{1}{3}-(2\frac{2}{5}-1\frac{1}{5})=4\frac{1}{3}-1\frac{1}{5}=4\frac{1\cdot5}{3\cdot5}-1\frac{1\cdot3}{5\cdot3}=4\frac{5}{15}-1\frac{3}{15}=3\frac{2}{15}\\[/tex]
