[tex] - 8 \div ( - 4) - ( - 6) \div 3 - 3 = 2 + 6 \div 3 - 3 = 2 + 2 - 3 = 4 - 3 = 1[/tex]

[tex]( - 6 + 6.4 - 10) \div ( - 8) \times ( - 3) = ( - 16 + 6.4)\div ( - 8) \times ( - 3) = - 9.6 \div ( - 8) \times ( - 3) =1.2 \times ( - 3) = - 3.6[/tex]

[tex]2 \frac{1}{5} \div( - 2) \times ( - 1.5) \div \frac{10}{11} = \frac{11 \times 3 \times 11}{5 \times 2 \times 2 \times 10} = \frac{363}{200} = 1 \frac{163}{200} = 1.815[/tex]

[tex](1.09 - 0.29) \times 1 \frac{1}{4} \div ((18.9 - 16 \frac{13}{20} ) \times \frac{8}{9} ) = 0.8 \times 1 \frac{1}{4} \div ((18.9 - 16.65) \times \frac{8}{9} ) = \frac{4 \times 5}{5 \times 4} \div (2.25 \times \frac{8}{9} ) =1 \div \frac{9 \times 8}{4\times 9} = 1 \div 2 = \frac{1}{2} = 0.5[/tex]