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1. 直接写得数。(6分)
3.5×2=
2.5×0.4=
9÷0.01=
3.5×2=
7
0.63÷9=0.07
100×0.9=90
1.5×6=9
2.5×0.4=
1
0.45÷0.3=1.5
0.54÷0.06=9
1.4-0.9=0.5
9÷0.01=
900
200×0.04=8
0.85-0.5=0.35
2.9÷10=0.29
答案
7；0.07；90；9；1；1.5；9；0.5；900；8；0.35；0.29
2. 用竖式计算。(6分)
3.04×4.5 9.12÷2.4 8.45÷3.7≈(精确到十分位)
3.04×4.5=13.68
3.04
× 4.5
------
1520
1216
------
13.680
9.12÷2.4=3.8
3.8
24)91.2
72
---
192
192
---
0
8.45÷3.7≈2.3
2.28
37)84.50
74
---
105
74
---
310
296
---
14
（精确到十分位，四舍五入得2.3）
3.04×4.5 9.12÷2.4 8.45÷3.7≈(精确到十分位)
3.04×4.5=13.68
3.04
× 4.5
------
1520
1216
------
13.680
9.12÷2.4=3.8
3.8
24)91.2
72
---
192
192
---
0
8.45÷3.7≈2.3
2.28
37)84.50
74
---
105
74
---
310
296
---
14
（精确到十分位，四舍五入得2.3）
答案
```
3.04×4.5=13.68
3.04
× 4.5
------
1520
1216
------
13.680
9.12÷2.4=3.8
3.8
24)91.2
72
---
192
192
---
0
8.45÷3.7≈2.3
2.28
37)84.50
74
---
105
74
---
310
296
---
14
（精确到十分位，四舍五入得2.3）
```
3.04×4.5=13.68
3.04
× 4.5
------
1520
1216
------
13.680
9.12÷2.4=3.8
3.8
24)91.2
72
---
192
192
---
0
8.45÷3.7≈2.3
2.28
37)84.50
74
---
105
74
---
310
296
---
14
（精确到十分位，四舍五入得2.3）
```
3. 脱式计算,怎样简便就怎样算。(8分)
10.1×4.2 3.8×101-3.8 0.25×3.2×1.25 9.4÷[(1.2+1.3)÷0.25]
10.1×4.2 3.8×101-3.8 0.25×3.2×1.25 9.4÷[(1.2+1.3)÷0.25]
答案
10.1×4.2
=(10+0.1)×4.2
=10×4.2+0.1×4.2
=42+0.42
=42.42
3.8×101-3.8
=3.8×(101-1)
=3.8×100
=380
0.25×3.2×1.25
=0.25×(4×0.8)×1.25
=(0.25×4)×(0.8×1.25)
=1×1
=1
9.4÷[(1.2+1.3)÷0.25]
=9.4÷[2.5÷0.25]
=9.4÷10
=0.94
=(10+0.1)×4.2
=10×4.2+0.1×4.2
=42+0.42
=42.42
3.8×101-3.8
=3.8×(101-1)
=3.8×100
=380
0.25×3.2×1.25
=0.25×(4×0.8)×1.25
=(0.25×4)×(0.8×1.25)
=1×1
=1
9.4÷[(1.2+1.3)÷0.25]
=9.4÷[2.5÷0.25]
=9.4÷10
=0.94
