a)
[tex]6 \frac{2}{7} - 4\frac{1}{7} = \frac{6\times 7 + 2}{7} - \frac{4 \times 7 + 1}{7} = \frac{44}{7} - \frac{29}{7} = \frac{44 - 29}{7} = \frac{15}{7} [/tex]
b)
[tex]12 \frac{1}{9} - 5 \frac{4}{9} = \frac{12 \times 9 + 1}{9} - \frac{5 \times 9 + 4}{9} = \frac{ 109}{9} - \frac{49}{9} = \frac{109 - 49}{9} = \frac{60}{9} = \frac{20}{3} [/tex]
c)
[tex]8 \frac{4}{5} - 3 \frac{1}{5} = \frac{8 \times 5 + 4}{5} - \frac{3 \times 5 + 1}{5} = \frac{44}{5} - \frac{16}{5} = \frac{44 - 16}{5} = \frac{28}{5} [/tex]
d)
[tex]18 \frac{2}{11} - 7\frac{5}{11} =\frac{18 \times 11 + 2}{11} - \frac{7 \times 11 + 5}{11} = \frac{200}{11} - \frac{82}{11} = \frac{200 - 82}{11} = \frac{118}{11} [/tex]
