[tex]a)\frac{7}{8} + \frac{3}{6} = \frac{7 \times 3}{8 \times 3} + \frac{3 \times 4}{6 \times 4} = \frac{21}{24} + \frac{12}{24} = \frac{21 + 12}{24} = { \frac{33}{24} }^{(3} = \frac{11}{8} = 1 \frac{3}{8} [/tex]
[tex]b) \frac{5}{3} - \frac{4}{9} = \frac{5 \times 3}{3 \times 3} - \frac{4}{9} = \frac{15}{9} - \frac{4}{9} = \frac{15 - 4}{9} = \frac{11}{9} = 1 \frac{2}{9} [/tex]
[tex]c) \frac{8}{9} \times \frac{3}{4} = \frac{8 \times 3}{9 \times 4} = { \frac{24}{36} }^{(12} = \frac{2}{3} [/tex]
