一、口算。(每题1分,共24分)
$1.4 - 0.6 = $ $5.1 ÷ 1.7 = $ $7.86 × 99 + 7.86 = $
$0.7 × 0.03 = $ $4.8 ÷ 0.24 = $ $2 × 0.8 ÷ 2 × 0.8 = $
$2.03 + 3.7 = $ $2.7 × 0.6 = $ $(0.2 - 0.2) × 4.8 = $
$3.6 ÷ 6 = $ $5 - 1.4 = $ $0.3 × (200 + 3) = $
$0.36 + 0.84 = $ $10 ÷ 0.25 = $ $6.5 + 7.8 + 3.05 = $
$0.18 ÷ 3.6 = $ $1.25 × 8 = $ $0.8 + 3.2 ÷ 0.08 = $
$10 - 0.01 = $ $5x - 4x = $ $9.63 × 101 - 9.63 = $
$4 ÷ 0.8 = $ $0.45 × 1000 = $ $3.7 × 4 ÷ 3.7 × 4 = $

0.8 3 786 0.021 20 0.64 5.73 1.62 0 0.6 3.6 60.9 1.2 40 17.35 0.05 10 40.8 9.99 x 963 5 450 16

$1.4 - 0.6 = 0.8$
$5.1 ÷ 1.7 = 3$
$7.86 × 99 + 7.86 = 786$
$0.7 × 0.03 = 0.021$
$4.8 ÷ 0.24 = 20$
$2 × 0.8 ÷ 2 × 0.8 = 0.64$
$2.03 + 3.7 = 5.73$
$2.7 × 0.6 = 1.62$
$(0.2 - 0.2) × 4.8 = 0$
$3.6 ÷ 6 = 0.6$
$5 - 1.4 = 3.6$
$0.3 × (200 + 3) = 60.9$
$0.36 + 0.84 = 1.2$
$10 ÷ 0.25 = 40$
$6.5 + 7.8 + 3.05 = 17.35$
$0.18 ÷ 3.6 = 0.05$
$1.25 × 8 = 10$
$0.8 + 3.2 ÷ 0.08 = 40.8$
$10 - 0.01 = 9.99$
$5x - 4x = x$
$9.63 × 101 - 9.63 = 963$
$4 ÷ 0.8 = 5$
$0.45 × 1000 = 450$
$3.7 × 4 ÷ 3.7 × 4 = 16$

二、用竖式计算,带*的要验算。(前2题每题3分,其余每题4分,共22分)
$9.3 - 2.67$ $36.8 + 4.98$ *$40.5 ÷ 18$
$0.48 × 5.04$ $0.988 ÷ 0.14$ *$2.9 × 0.036$
(得数保留两位小数) (得数保留一位小数)

6.63 41.78 2.25 2.42 7.1 0.1044

$9.3 - 2.67 = 6.63$
```
9.30
2.67
------
6.63
```
$36.8 + 4.98 = 41.78$
```
36.80
+ 4.98
------
41.78
```
*$40.5 ÷ 18 = 2.25$
```
2.25
18)40.50
36
---
45
36
---
90
90
---
0
```
验算：
```
2.25
× 18
-----
18.00
22.50
-----
40.50
```
$0.48 × 5.04 ≈ 2.42$（保留两位小数）
```
5.04
×0.48
------
4032
2016
------
2.4192
```
$0.988 ÷ 0.14 ≈ 7.1$（保留一位小数）
```
7.057...
0.14)0.9880
98
---
80
70
---
100
98
---
2
```
*$2.9 × 0.036 = 0.1044$
```
2.9
×0.036
------
174
87
------
0.1044
```
验算：
```
0.036
× 2.9
------
324
72
------
0.1044
```

三、计算下面各题,怎样简便就怎样计算。(每题4分,共32分)
$820 - 5.89 × 99 - 5.89$ $2.76 ÷ 0.4 ÷ (2.99 - 2.74)$
$888 × 0.33 + 0.34 × 444$ $30.5 - 1.8 × 0.42 ÷ 5.4$
$15.6 × 13.1 - 15.6 - 15.6 × 2.1$ $4.2 ÷ [3.6 - (13.78 - 10.88)]$
$47.5 - (0.74 + 8.64 ÷ 3.2)$ $28.25 - (17.25 + 6.42) - 4.58$

231 27.6 444 30.36 156 6 44.06 0

1. $820 - 5.89×99 - 5.89$
$\begin{aligned}&=820 - 5.89×(99 + 1)\\&=820 - 5.89×100\\&=820 - 589\\&=231\end{aligned}$
2. $2.76÷0.4÷(2.99 - 2.74)$
$\begin{aligned}&=2.76÷0.4÷0.25\\&=2.76÷(0.4×0.25)\\&=2.76÷0.1\\&=27.6\end{aligned}$
3. $888×0.33 + 0.34×444$
$\begin{aligned}&=444×2×0.33 + 0.34×444\\&=444×(0.66 + 0.34)\\&=444×1\\&=444\end{aligned}$
4. $30.5 - 1.8×0.42÷5.4$
$\begin{aligned}&=30.5 - (1.8÷5.4)×0.42\\&=30.5 - \frac{1}{3}×0.42\\&=30.5 - 0.14\\&=30.36\end{aligned}$
5. $15.6×13.1 - 15.6 - 15.6×2.1$
$\begin{aligned}&=15.6×(13.1 - 1 - 2.1)\\&=15.6×10\\&=156\end{aligned}$
6. $4.2÷[3.6 - (13.78 - 10.88)]$
$\begin{aligned}&=4.2÷[3.6 - 2.9]\\&=4.2÷0.7\\&=6\end{aligned}$
7. $47.5 - (0.74 + 8.64÷3.2)$
$\begin{aligned}&=47.5 - (0.74 + 2.7)\\&=47.5 - 3.44\\&=44.06\end{aligned}$
8. $28.25 - (17.25 + 6.42) - 4.58$
$\begin{aligned}&=28.25 - 17.25 - 6.42 - 4.58\\&=(28.25 - 17.25) - (6.42 + 4.58)\\&=11 - 11\\&=0\end{aligned}$