1.直接写出得数。
0.54×5=
0.43×7=
0.4×40=
0.32×0.8=
13.3÷7=
24.65÷5=
7.2÷3=
2.8÷7=
12+0.8=
1.2+9.7=
13-4.1=
8.66-5=

0.54×5=2.7
0.43×7=3.01
0.4×40=16
0.32×0.8=0.256
13.3÷7=1.9
24.65÷5=4.93
7.2÷3=2.4
2.8÷7=0.4
12+0.8=12.8
1.2+9.7=10.9
13-4.1=8.9
8.66-5=3.66

2.列竖式计算。
3.24×0.35=
16.2÷0.45=
30.2÷4.8≈
（得数保留一位小数）

3.24×0.35
```
3.24
×0.35
------
1620
972
------
1.1340
```
$3.24×0.35=1.134$
---
16.2÷0.45
```
36
-------
45)1620
135
----
270
270
----
0
```
$16.2÷0.45=36$
---
30.2÷4.8（得数保留一位小数）
```
6.29
---------
48)302.00
288
-----
140
96
-----
440
432
-----
8
```
$30.2÷4.8≈6.3$

3. 计算下面各题,能简算的要简算。
76.4÷0.25÷4
2.5×(8+0.4)
(28.2+1.8)÷0.15×4
1.25×2.27×0.8
2.5×0.36
0.59×99+0.59

76.4÷0.25÷4
=76.4÷(0.25×4)
=76.4÷1
=76.4
2.5×(8+0.4)
=2.5×8 + 2.5×0.4
=20 + 1
=21
(28.2+1.8)÷0.15×4
=30÷0.15×4
=200×4
=800
1.25×2.27×0.8
=1.25×0.8×2.27
=1×2.27
=2.27
2.5×0.36
=2.5×4×0.09
=10×0.09
=0.9
0.59×99+0.59
=0.59×(99+1)
=0.59×100
=59

4. 根据$123×26=3198$，在括号里填上合适的数。
$123×260=(\quad\quad\quad\quad)$
$1.23×26=(\quad\quad\quad\quad)$
$123×2.6=(\quad\quad\quad\quad)$
$(\quad\quad\quad\quad)×26=3.198$
$(\quad\quad\quad\quad)×0.26=31.98$
$12.3×(\quad\quad\quad\quad)=319.8$

$123×260=(31980)$
$1.23×26=(31.98)$
$123×2.6=(319.8)$
$(0.123)×26=3.198$
$(123)×0.26=31.98$
$12.3×(26)=319.8$