一、直接写出得数。(每题1分,共32分)
0.1×5=
1.4×2=
0.99÷11=
20×0.3÷10=
0.2×0.3=
8.65×0=
15.4×100=
40÷10×0.5=
4.8÷6=
0.5×0.8=
3.2×0.7=
500×0.2÷100=
0.7×10=
0.4×0.6=
7.1×0.8=
1.05÷5÷3=
10.8÷100=
0.08÷8=
5.2×0.2=
0.9×9×10=
10.5÷5=
6.66÷3=
1.6×0.3=
102÷100×1000=
0.24×0.2=
3.9÷3=
2.4×2.5=
24.6÷6÷10=
1.1×20=
4.5÷9=
8.5×0.8=
0.33÷11×10=
0.1×5=
0.5
1.4×2=
2.8
0.99÷11=
0.09
20×0.3÷10=
0.6
0.2×0.3=
0.06
8.65×0=
0
15.4×100=
1540
40÷10×0.5=
2
4.8÷6=
0.8
0.5×0.8=
0.4
3.2×0.7=
2.24
500×0.2÷100=
1
0.7×10=
7
0.4×0.6=
0.24
7.1×0.8=
5.68
1.05÷5÷3=
0.07
10.8÷100=
0.108
0.08÷8=
0.01
5.2×0.2=
1.04
0.9×9×10=
81
10.5÷5=
2.1
6.66÷3=
2.22
1.6×0.3=
0.48
102÷100×1000=
1020
0.24×0.2=
0.048
3.9÷3=
1.3
2.4×2.5=
6
24.6÷6÷10=
0.41
1.1×20=
22
4.5÷9=
0.5
8.5×0.8=
6.8
0.33÷11×10=
0.3
答案
0.5 2.8 0.09 0.6 0.06 0 1540 2 0.8 0.4 2.24 1 7 0.24 5.68 0.07 0.108 0.01 1.04 81 2.1 2.22 0.48 1020 0.048 1.3 6 0.41 22 0.5 6.8 0.3
二、用竖式计算,带☆的要验算。(每题3分,验算各1分,共20分)
4.8×50=
0.83×0.9=
16÷25=
☆36×2.4=
90.2×6.7≈
(得数保留一位小数)
☆19.62÷18=
4.8×50=
240
0.83×0.9=
0.747
16÷25=
0.64
☆36×2.4=
86.4
90.2×6.7≈
604.3
(得数保留一位小数)
☆19.62÷18=
1.09
答案
240 0.747 0.64 86.4 604.3 1.09 竖式及验算略
解析
```
4.8
× 50
----
240.0
0.83
× 0.9
----
0.747
0.64
25)16.00
150
----
100
100
----
0
36
×2.4
----
144
72
----
86.4
验算:
2.4
×36
----
144
72
----
86.4
90.2
× 6.7
----
6314
5412
----
604.34 ≈ 604.3
1.09
18)19.62
18
----
162
162
----
0
验算:
1.09
× 18
----
872
109
----
19.62
```
4.8
× 50
----
240.0
0.83
× 0.9
----
0.747
0.64
25)16.00
150
----
100
100
----
0
36
×2.4
----
144
72
----
86.4
验算:
2.4
×36
----
144
72
----
86.4
90.2
× 6.7
----
6314
5412
----
604.34 ≈ 604.3
1.09
18)19.62
18
----
162
162
----
0
验算:
1.09
× 18
----
872
109
----
19.62
```
三、计算下面各题,能简算的要简算。(每题3分,共18分)
0.78+4.23+6.22+5.77
0.138×2.5×4
0.76÷0.8÷5
18.7-5.5-7.2+4.9
4.49-0.64-0.36
0.125×68×32
0.78+4.23+6.22+5.77
0.138×2.5×4
0.76÷0.8÷5
18.7-5.5-7.2+4.9
4.49-0.64-0.36
0.125×68×32
答案
17 1.38 0.19 10.9 3.49 272
解析
0.78+4.23+6.22+5.77
=(0.78+6.22)+(4.23+5.77)
=7+10
=17
0.138×2.5×4
=0.138×(2.5×4)
=0.138×10
=1.38
0.76÷0.8÷5
=0.76÷(0.8×5)
=0.76÷4
=0.19
18.7-5.5-7.2+4.9
=(18.7+4.9)-(5.5+7.2)
=23.6-12.7
=10.9
4.49-0.64-0.36
=4.49-(0.64+0.36)
=4.49-1
=3.49
0.125×68×32
=0.125×68×8×4
=(0.125×8)×(68×4)
=1×272
=272
=(0.78+6.22)+(4.23+5.77)
=7+10
=17
0.138×2.5×4
=0.138×(2.5×4)
=0.138×10
=1.38
0.76÷0.8÷5
=0.76÷(0.8×5)
=0.76÷4
=0.19
18.7-5.5-7.2+4.9
=(18.7+4.9)-(5.5+7.2)
=23.6-12.7
=10.9
4.49-0.64-0.36
=4.49-(0.64+0.36)
=4.49-1
=3.49
0.125×68×32
=0.125×68×8×4
=(0.125×8)×(68×4)
=1×272
=272
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