二、计算下面各题，怎样简便就怎样计算。
$105×13 - 1890÷18$
$\frac{5}{7} - (\frac{4}{9} - \frac{2}{7})$
$(20.2×0.4 + 7.88)÷4.2$
$1.25×2.6×0.8$
$1÷8 + \frac{1}{8}×99 - \frac{1}{2}$
$(3.75 + 4.1 + 2.35)×9.8$
$\frac{5}{6}÷[80\%×(\frac{1}{8} - \frac{1}{9})]$
$\frac{2}{7}÷[\frac{24}{13}×(\frac{2}{3} + \frac{7}{9})]$
$0.4×[1.4 - (2.4 - 2.25)]$
$\frac{17}{12}×\frac{1}{7} - \frac{5}{12}÷7$
$(\frac{11}{12} + \frac{1}{19})×12 + \frac{7}{19}$
$5.65 - 0.75 + 0.25 - 1.35$
$\frac{5}{7} - \frac{3}{5}×\frac{3}{14}÷\frac{9}{10}$
$4.8×3.67 + 4.8×6.33$
$90\%÷[50\%×(\frac{6}{5} - \frac{3}{10})]$

二、1260 $\dfrac{5}{9}$ 3.8
2.6 12 99.96
75 $\dfrac{3}{28}$ 0.5
$\dfrac{1}{7}$ 12 3.8
 
$\dfrac{4}{7}$ 48 2