1. 直接写出得数。
$0.4 + 5.8 =$ $3.8 + 0.02 =$ $33 ÷ 1.1 =$ $7.2 - 1.2 + 6.7 =$
$4.8 ÷ 0.6 =$ $21.5 + 9 =$ $5.01 ÷ 3 =$ $16 - 4.5 - 5.5 =$
$1 - 0.43 =$ $3 × 1.2 =$ $54 × 0.5 =$ $(1.6 + 2.4) ÷ 5 =$
$8 - 3.6 =$ $2.6 × 4 =$ $5.5 - 1.52 =$ $25 × 3.3 × 4 =$
$0.89 - 0.5 =$ $0.8 × 0.9 =$ $0.25 × 16 =$ $1.9 + 5.1 ÷ 51 =$
$0.36 ÷ 3.6 =$ $8.1 ÷ 0.3 =$ $8.01 ÷ 3 =$ $(1 - 0.1) × 0.1 =$

1. 6.2 3.82 30 12.7
8 30.5 1.67 6
0.57 3.6 27 0.8
4.4 10.4 3.98 330
0.39 0.72 4 2
0.1 27 2.67 0.09

2. 解方程。
$\frac{1}{7} + x = \frac{2}{3}$ $1.44x - x = 1.32$ $1.8x ÷ 5 = 0.9$

2. $ x=\frac{11}{21} $ $ x=3 $ $ x=2.5 $

3. 计算下面长方体、正方体涂色面的面积。

3. (1) $ 5×6=30(cm^{2}) $
(2) $ 3×3=9(cm^{2}) $
(3) $ 0.8×0.8=0.64(m^{2}) $

(1) 计算：$32.4 × 6.28 - 3.14 × 54.8$。

(1) 原式 $ =64.8×3.14-3.14×54.8 $
$ =(64.8-54.8)×3.14 $
$ =10×3.14 $
$ =31.4 $

(2) 计算：$1.11 × 48 + 444 × 0.88$。

(2) 原式 $ =111×0.48+444×0.88 $
$ =444×0.12+444×0.88 $
$ =444×(0.12+0.88) $
$ =444 $