一、用竖式计算,带*的要验算。
$51.2÷1.6$ $6.85×7.8$ *$3.678+0.99$
(得数保留一位小数)
$7-0.162$ $2.113÷1.5$ *$0.26×0.705$
(得数保留两位小数)
$35.49÷3.9$ $1.85×0.32$ *$1.62÷0.27$
(得数保留两位小数)

一、32 53.4 4.668 6.838 1.41 0.1833 9.1 0.59 6

1. $51.2÷1.6$
```
32
1.6)51.2
48
---
32
32
---
0
```
=32
2. $6.85×7.8$
```
6.85
× 7.8
-----
5480
4795
-----
53.430
```
≈53.4
3. $3.678 + 0.99$
```
3.678
+ 0.99
------
4.668
```
验算：
```
4.668
0.99
------
3.678
```
=4.668
4. $7 - 0.162$
```
7.000
0.162
------
6.838
```
=6.838
5. $2.113÷1.5$
```
1.4086...
1.5)21.1300
15
---
61
60
---
130
120
---
100
90
---
10
```
≈1.41
6. $0.26×0.705$
```
0.705
× 0.26
------
4230
1410
------
0.18330
```
验算：
```
0.705
× 0.26
------
4230
1410
------
0.18330
```
=0.1833
7. $35.49÷3.9$
```
9.1
3.9)354.9
351
---
39
39
---
0
```
=9.1
8. $1.85×0.32$
```
1.85
× 0.32
------
370
555
------
0.5920
```
≈0.59
9. $1.62÷0.27$
```
6
0.27)1.62
1.62
---
0
```
验算：
```
0.27
× 6
------
1.62
```
=6

二、计算下面各题,怎样简便就怎样计算。
$8.36×10.1$ $0.25×3.2×1.25$
$7.75÷2.5÷0.4$ $12.47-(6.5-0.47)-3.5$
$10.4-1.9×0.6÷7.6$ $2.87÷(2.87×0.4)÷0.5$
$(15.5×6+6×8.5)÷8$ $2.3×[(3.35-2.66)÷0.3]$

二、84.436 1 7.75 2.94 10.25 5 18 5.29

$8.36×10.1$
$=8.36×(10 + 0.1)$
$=8.36×10 + 8.36×0.1$
$=83.6 + 0.836$
$=84.436$
$0.25×3.2×1.25$
$=0.25×(4×0.8)×1.25$
$=(0.25×4)×(0.8×1.25)$
$=1×1$
$=1$
$7.75÷2.5÷0.4$
$=7.75÷(2.5×0.4)$
$=7.75÷1$
$=7.75$
$12.47-(6.5 - 0.47)-3.5$
$=12.47 - 6.5 + 0.47 - 3.5$
$=(12.47 + 0.47)-(6.5 + 3.5)$
$=12.94 - 10$
$=2.94$
$10.4 - 1.9×0.6÷7.6$
$=10.4 - 1.14÷7.6$
$=10.4 - 0.15$
$=10.25$
$2.87÷(2.87×0.4)÷0.5$
$=2.87÷2.87÷0.4÷0.5$
$=1÷(0.4×0.5)$
$=1÷0.2$
$=5$
$(15.5×6 + 6×8.5)÷8$
$=6×(15.5 + 8.5)÷8$
$=6×24÷8$
$=144÷8$
$=18$
$2.3×[(3.35 - 2.66)÷0.3]$
$=2.3×[0.69÷0.3]$
$=2.3×2.3$
$=5.29$