4. 计算。
(1)用竖式计算。(除不尽的,得数保留两位小数)$6.4×0.29$ $12.4×0.75$ $6.9÷0.54$ $18.9÷15.12$ $7.36÷18$ $2.08×7.5$
(2)用你喜欢的方法计算。$12.75+[14.6-(1.4+8.2)]$ $83×10.1$ $0.18×7.4+2.6×0.18$ $[8.5-(3.6+3.6)]÷2.6$ $1.25×0.32×25$ $19.2÷2.4×0.15$

(1)
$6.4×0.29=1.856$
```
6.4
×0.29
-----
576
128
-----
1.856
```
$12.4×0.75=9.3$
```
12.4
×0.75
-----
620
868
-----
9.300
```
$6.9÷0.54\approx12.78$
```
12.777...
0.54|690.000
54
---
150
108
---
420
378
---
420
378
---
420
378
---
42
```
$18.9÷15.12=1.25$
```
1.25
15.12|18.9000
15.12
------
3.7800
3.0240
------
0.7560
0.7560
------
0
```
$7.36÷18\approx0.41$
```
0.408...
18|7.3600
7.2
---
0.160
0.144
---
0.0160
0.0144
---
0.0016
```
$2.08×7.5=15.6$
```
2.08
×7.5
-----
1040
1456
-----
15.600
```
(2)
$12.75+[14.6-(1.4+8.2)]$
$=12.75+[14.6-9.6]$
$=12.75+5$
$=17.75$
$83×10.1$
$=83×(10+0.1)$
$=83×10+83×0.1$
$=830+8.3$
$=838.3$
$0.18×7.4+2.6×0.18$
$=0.18×(7.4+2.6)$
$=0.18×10$
$=1.8$
$[8.5-(3.6+3.6)]÷2.6$
$=[8.5-7.2]÷2.6$
$=1.3÷2.6$
$=0.5$
$1.25×0.32×25$
$=1.25×0.08×4×25$
$=(1.25×0.08)×(4×25)$
$=0.1×100$
$=10$
$19.2÷2.4×0.15$
$=8×0.15$
$=1.2$