[tex] - 8 \frac{4}{7} - ( - 6 \frac{3}{5} ) - 9 \frac{2}{5 } - 1.6 - 6 \frac{3}{7} = - 15 + 6.6 - 9.4 - 1.6 = - 15 + 6.6 - 11 = - 26 + 6.6 = - 19.4[/tex]