四、一丝不苟，精打细算。
1.直接写出得数。
0.4×2.5=
0.8×1.25=
0.3×3.6=
0.3×0.3=
0.3×1.4=
0.92×0.4=
0.2×0.26=
0.14×4=

0.4×2.5=1
0.8×1.25=1
0.3×3.6=1.08
0.3×0.3=0.09
0.3×1.4=0.42
0.92×0.4=0.368
0.2×0.26=0.052
0.14×4=0.56

2.列竖式计算下面各题(带☆的得数保留两位小数,带△的得数保留一位小数)。
0.42×3.7=
☆6.03×0.25≈
1.2×0.025=
△1.32×6.8≈

0.42×3.7=1.554
```
0.42
× 3.7
-------
294
126
-------
1.554
```
---
☆6.03×0.25≈1.51
```
6.03
× 0.25
-------
3015
1206
-------
1.5075
```
---
1.2×0.025=0.03
```
1.2
×0.025
-------
60
24
-------
0.0300
```
---
△1.32×6.8≈9.0
```
1.32
× 6.8
-------
1056
792
-------
8.976
```

3. 用你喜欢的方法计算。
(1)$16.2×4.3 - 4.3×6.2$
(2)$0.25×0.125×8$
(3)$4.2×0.5 + 0.5$

(1)
$16.2×4.3 - 4.3×6.2$
$=4.3×(16.2 - 6.2)$
$=4.3×10$
$=43$
(2)
$0.25×0.125×8$
$=0.25×(0.125×8)$
$=0.25×1$
$=0.25$
(3)
$4.2×0.5 + 0.5$
$=0.5×(4.2 + 1)$
$=0.5×5.2$
$=2.6$