1. 直接写出得数。
$81 + 109 =$
$6.3 ÷ 0.21 =$
$0.5 : 4.5 =$
$0.5 + 0.5 × 0.6 =$
$1.8 × 4 =$
$372 - 66 =$
$2 : \frac{2}{5} =$
$0.6 × 101 - 0.6 =$
$4.3 × 0.5 =$
$2.01 ÷ 3 =$
$5 : \frac{5}{8} =$
$0.8 × 0.7 × 0 =$
$1.1 × 2 =$
$1.2 × 0.8 =$
$0.8 : \frac{2}{5} =$
$3.72 + 1.58 - 0.72 =$
$0 ÷ \frac{5}{8} =$
$6.6 + 7.8 =$
$\frac{2}{5} : \frac{2}{3} =$
$\frac{7}{12} + ( \frac{9}{10} + \frac{5}{12} ) =$
$\frac{3}{5} ÷ 5 =$
$\frac{4}{5} × \frac{7}{4} =$
$0.15 : \frac{3}{10} =$
$5 ÷ \frac{7}{8} ÷ \frac{4}{21} =$
$\frac{2}{3} × \frac{5}{9} =$
$\frac{1}{18} ÷ 0.25 =$
$\frac{15}{17} : \frac{5}{34} =$
$\frac{18}{25} ÷ ( \frac{3}{5} × \frac{2}{5} ) =$
$\frac{5}{18} × 1 =$
$15 ÷ \frac{3}{26} =$
$\frac{1}{4} : \frac{1}{5} =$
$\frac{3}{7} - ( \frac{4}{5} - \frac{4}{7} ) =$

1. 190
30
$\frac{1}{9}$
0.8
7.2
306
5
60
2.15
0.67
8
0
2.2
0.96
2
4.58
0
14.4
$\frac{3}{5}$
$1\frac{9}{10}$
$\frac{3}{25}$
$\frac{7}{5}$
$\frac{1}{2}$
30
$\frac{10}{27}$
$\frac{2}{9}$
6
3
$\frac{5}{18}$
130
$\frac{5}{4}$
$\frac{1}{5}$

2. 计算下面各题，怎样算简便就怎样算。
$24÷ 1.6÷ 0.5$
$3.68+[(5-3.56)÷ 1.2]$
$5.4× 3.8+2.7× 2.4$
$90× (1-0.5+\dfrac{2}{9})$
$12÷ (1-\dfrac{1}{4})× \dfrac{1}{8}$
$[\dfrac{13}{9}-(\dfrac{2}{3}+\dfrac{1}{2})]÷ \dfrac{5}{21}$

2. 30
4.88
27
65
2
$\frac{7}{6}$

在一道减法算式中，被减数、减数和差的和是192，减数与差的比是7：9，被减数是（），减数是（）。

96
42