[tex]A=\frac{18}{5}+ \frac{3}{5}= \frac{18+3}{5} =\frac{21}{5}[/tex]
[tex]B=\frac{2}{7}+ \frac{5}{7}= \frac{2+5}{7} =\frac{9}{7}[/tex]
[tex] C=\frac{6}{13}+\frac{12}{13}-\frac{1}{13}=\frac{6+12-1}{13}=\frac{17}{13} [/tex]
[tex] D=\frac{4}{9}-\frac{11}{9}= \frac{4-11}{9}=\frac{-7}{9} [/tex]
[tex]E=\frac{5}{6}+\frac{5}{12}=\frac{5*2}{6*2}+\frac{5}{12}=\frac{10}{12}+\frac{5}{12} =\frac{15}{12} =\frac{5*3}{4*3} =\frac{5}{4}[/tex]
[tex] F=\frac{2}{7}-\frac{1}{56}=\frac{2*8}{7*8}-\frac{1}{56}=\frac{16}{56}-\frac{1}{56}=\frac{15}{56} [/tex]
[tex] G=\frac{1}{2}+\frac{1}{4}+\frac{1}{8}=\frac{4}{8}+\frac{2}{8}+\frac{1}{8}=\frac{7}{8}[/tex]
[tex]H=\frac{11}{1,3} -\frac{5}{26}=\frac{11*20}{1,3*20}-\frac{5}{26}=\frac{220}{26}-\frac{5}{26}=\frac{215}{26}[/tex]
[tex]J=\frac{-2,7}{45}+\frac{1,3}{135}=\frac{-2,7*3}{45*3}+\frac{1,3}{135}=\frac{-8,1}{135}+\frac{1,3}{135}=\frac{-6,8}{135}[/tex]
[tex]K=\frac{5}{21} +\frac{-3}{14}=\frac{5*2}{21*2}+\frac{-3*3}{14*3}=\frac{10}{42}+\frac{-9}{42}=\frac{10-9}{42}=\frac{1}{42}[/tex]
[tex] L=4-\frac{-2}{17}+\frac{3}{-34} =\frac{4*34}{34}-\frac{-2*2}{17*2}+\frac{-3}{34}=\frac{136}{34}-\frac{-4}{34}+\frac{-3}{34}=\frac{136}{34}+\frac{4}{34}-\frac{3}{34}[/tex]
Donc [tex] L=\frac{136+4-3}{34}=\frac{137}{34}[/tex]
[tex] M=\frac{-5}{44}-\frac{4}{55} =\frac{-5}{4*11}-\frac{4}{5*11}=\frac{-5*5}{4*11*5}-\frac{4*4}{5*11*4}=\frac{-25}{220}-\frac{16}{220}=\frac{-41}{220}[/tex]
