$\frac{1}{2}+\frac{3}{5}=\frac{5}{10}+\frac{6}{10}=\frac{5+6}{10}=\frac{11}{10}\backslash frac\{1\}\{2\}+\backslash frac\{3\}\{5\}=\backslash frac\{5\}\{10\}+\backslash frac\{6\}\{10\}=\backslash frac\{5+6\}\{10\}=\backslash frac\{11\}\{10\}$

${\displaystyle \frac{3}{4}}+{\displaystyle \frac{2}{5}}={\displaystyle \frac{15}{20}}+{\displaystyle \frac{8}{20}}={\displaystyle \frac{15+8}{20}}={\displaystyle \frac{23}{20}}\backslash dfrac\{3\}\{4\}+\backslash dfrac\{2\}\{5\}=\backslash dfrac\{15\}\{20\}+\backslash dfrac\{8\}\{20\}=\backslash dfrac\{15+8\}\{20\}=\backslash dfrac\{23\}\{20\}$

${\displaystyle \frac{4}{5}}-{\displaystyle \frac{1}{7}}={\displaystyle \frac{28}{35}}-{\displaystyle \frac{5}{35}}={\displaystyle \frac{28-5}{35}}={\displaystyle \frac{23}{35}}\backslash dfrac\{4\}\{5\}-\backslash dfrac\{1\}\{7\}=\backslash dfrac\{28\}\{35\}-\backslash dfrac\{5\}\{35\}=\backslash dfrac\{28-5\}\{35\}=\backslash dfrac\{23\}\{35\}$

${\displaystyle \frac{4}{5}}-{\displaystyle \frac{1}{7}}={\displaystyle \frac{28}{35}}-{\displaystyle \frac{5}{35}}={\displaystyle \frac{28-5}{35}}={\displaystyle \frac{23}{35}}\backslash dfrac\{4\}\{5\}-\backslash dfrac\{1\}\{7\}=\backslash dfrac\{28\}\{35\}-\backslash dfrac\{5\}\{35\}=\backslash dfrac\{28-5\}\{35\}=\backslash dfrac\{23\}\{35\}$