Número 1; Letra A:
[tex] \frac{3}{5} + \frac{4}{5} = \frac{7}{5} [/tex]
Letra B:
[tex] \frac{2}{7} + \frac{8}{7} = \frac{10}{7} [/tex]
Letra C:
[tex] \frac{3}{1} + \frac{2}{2} = \frac{6}{2} + \frac{2}{2} = \frac{8}{2} [/tex]
Letra D:
[tex] \frac{2}{7} + \frac{2}{3} = \frac{6}{21} + \frac{14}{21} = \frac{20}{21} [/tex]
Número 2; Letra A:
[tex] \frac{4}{2} - \frac{1}{2} = \frac{3}{2} [/tex]
Letra B:
[tex] \frac{6}{5} - \frac{3}{5} = \frac{3}{5} [/tex]
Letra C:
[tex] \frac{5}{2} - \frac{3}{1} = \frac{5}{2} - \frac{6}{2} = - \frac{1}{2} [/tex]
Letra D:
[tex] \frac{3}{6} - \frac{2}{5} = \frac{15}{30} - \frac{12}{30} = \frac{3}{30} [/tex]
Número 3; Letra A:
[tex] \frac{3}{7} \times \frac{2}{3} = \frac{6}{21} [/tex]
Letra B:
[tex] \frac{5}{8} \times \frac{3}{2} = \frac{15}{16} [/tex]
Letra C:
[tex] \frac{6}{2} \times \frac{3}{7} = \frac{18}{14} [/tex]
Letra D:
[tex] \frac{3}{9} \times \frac{2}{5} = \frac{6}{45} [/tex]
Número 4; Letra A:
[tex] \frac{7}{2} \div \frac{5}{3} = \frac{7}{2} \times \frac{3}{5} = \frac{21}{10} [/tex]
Letra B:
[tex] \frac{4}{3} \div \frac{6}{5} = \frac{4}{3} \times \frac{5}{6} = \frac{20}{18} [/tex]
Letra C:
[tex] \frac{3}{2} \div \frac{4}{5} = \frac{3}{2} \times \frac{5}{4} = \frac{15}{8} [/tex]
Letra D:
[tex] \frac{8}{5} \div \frac{4}{6} = \frac{8}{5} \times \frac{6}{4} = \frac{48}{20} [/tex]
Espero ter ajudado ;)
