一、直接写出得数。(每题1分,共32分)
3.9-1.3=
1.5+1.4=
0.56+0.8=
0.9+3÷10=
1.4+2.6=
0.68÷17=
0.7-0.04=
5×0.12+4=
18÷900=
0.26×5=
4.8×0.5=
7×(0.62÷2)=
2.5÷5=
1.7÷0.85=
60×3.2=
0.16÷8÷2=
3.2×0.7=
0.72×100=
0.72÷0.6=
10÷0.4×8=
0.49÷7=
4.4×2.5=
2.8×30=
3.3÷11+5.2=
0.6y+1.4y=
4.7x-2.5x=
4b×a=
0.48m÷0.12-0.8m=
0.8a-0.3a=
2.6a×2=
1.2a×0.1=
2.8x×0.2÷0.1=

2.6 2.9 1.36 1.2 4 0.04 0.66 4.6 0.02 1.3 2.4 2.17 0.5 2 192 0.01 2.24 72 1.2 200 0.07 11 84 5.5 2y 2.2x 4ab 3.2m 0.5a 5.2a 0.12a 5.6x

二、用竖式计算,带☆的要验算。(每题3分,验算各1分,共21分)
☆7.6-1.87=
☆3.5×0.46=
1.8÷0.24=
6.72×1.5=
☆8.32÷2.6=
2.25×5.6=
竖式及验算略

85.73 1.61 7.5 10.08 3.2 12.6 竖式及验算略

```
☆7.6-1.87=5.73
7.60
1.87
------
5.73
验算：
5.73
+ 1.87
------
7.60
☆3.5×0.46=1.61
3.5
×0.46
------
210
140
------
1.610
验算：
0.46
×3.5
------
230
138
------
1.610
1.8÷0.24=7.5
7.5
0.24)1.80.0
1.68
------
0.120
0.120
------
0
6.72×1.5=10.08
6.72
× 1.5
------
3360
672
------
10.080
☆8.32÷2.6=3.2
3.2
2.6)8.3.2
7.8
------
0.52
0.52
------
0
验算：
3.2
×2.6
------
192
64
------
8.32
2.25×5.6=12.6
2.25
× 5.6
------
1350
1125
------
12.600
```

三、计算下面各题,能简算的要简算。(每题3分,共18分)
6.89×101
6.75-0.45-1.55
3.75×98+3.75+3.75
7.5×3.8+6.2×7.5
(43.6-18.9)÷2.5÷0.4
4.8÷[1.6×(6.5+3.5)]

695.89 4.75 375 75 24.7 0.3

6.89×101
=6.89×(100+1)
=6.89×100+6.89×1
=689+6.89
=695.89
6.75-0.45-1.55
=6.75-(0.45+1.55)
=6.75-2
=4.75
3.75×98+3.75+3.75
=3.75×(98+1+1)
=3.75×100
=375
7.5×3.8+6.2×7.5
=7.5×(3.8+6.2)
=7.5×10
=75
(43.6-18.9)÷2.5÷0.4
=24.7÷(2.5×0.4)
=24.7÷1
=24.7
4.8÷[1.6×(6.5+3.5)]
=4.8÷[1.6×10]
=4.8÷16
=0.3