1. 直接写出得数。(每题0.5分,共4分)
$1.2 + 0.08 = $ $0.5×0.4 = $ $5 - 2×0.3 = $
$0.56÷0.8 = $ $0.44 - 0.4 = $ $9×2.4 + 2.4 = $
$0.9×30 = $ $0.25×4÷0.25×4 = $

1.28　0.2　4.4　0.7　0.04　24　27　16

2. 用竖式计算,带※的要验算。(带※的每题3分,其余每题2分,共9分)
$3.08×8.25 = $ $6.192÷2.4 = $
※$45.9÷0.17 = $ $3.61÷0.87 ≈$
(得数保留两位小数)

25.41　2.58　270　4.15

```
3.08
×8.25
------
1540
616
2464
------
25.4100
6.192÷2.4=2.58
45.9÷0.17=270
验算：
0.17
×270
------
119
34
------
45.90
3.61÷0.87≈4.15
```

3. 计算下面各题,能简算的要简算。(每题2分,共12分)
$54÷3.6$ $18.75÷3.75 + 18.75÷6.25$
$7.26÷0.25÷0.4$ $6.87×[40÷(3.49 - 3.09)]$
$(2.89 + 2.89×7)×1.25$ $51.2×48 + 5.12×520$

15　8　72.6　687　28.9　5120

$54÷3.6=15$
$18.75÷3.75 + 18.75÷6.25=5+3=8$
$7.26÷0.25÷0.4=7.26÷(0.25×0.4)=7.26÷0.1=72.6$
$6.87×[40÷(3.49 - 3.09)]=6.87×(40÷0.4)=6.87×100=687$
$(2.89 + 2.89×7)×1.25=2.89×(1 + 7)×1.25=2.89×8×1.25=2.89×10=28.9$
$51.2×48 + 5.12×520=51.2×48 + 51.2×52=51.2×(48 + 52)=51.2×100=5120$

1. $1.4$的$7.5$倍是,()的$0.6$倍是$13.2$,$18$是$8$的倍。＞举一反三

10.5　22　2.25

1.4×7.5=10.5
13.2÷0.6=22
18÷8=2.25
10.5　22　2.25