1. (1) 根据 $236 × 27 = 6372$,直接写出下面各题的得数。
$23.6 × 27 =$ $2.36 × 27 =$ $0.236 × 27 =$ $0.027 × 236 =$
(2) 根据 $144 × 25 = 3600$,直接写出下面各题的得数。
$14.4 × 25 =$ $1.44 × 25 =$ $0.144 × 25 =$ $2.5 × 144 =$
$23.6 × 27 =$ $2.36 × 27 =$ $0.236 × 27 =$ $0.027 × 236 =$
(2) 根据 $144 × 25 = 3600$,直接写出下面各题的得数。
$14.4 × 25 =$ $1.44 × 25 =$ $0.144 × 25 =$ $2.5 × 144 =$
答案
(1)
$23.6×27=637.2$
$2.36×27=63.72$
$0.236×27=6.372$
$0.027×236=6.372$
(2)
$14.4×25=360$
$1.44×25=36$
$0.144×25=3.6$
$2.5×144=360$
$23.6×27=637.2$
$2.36×27=63.72$
$0.236×27=6.372$
$0.027×236=6.372$
(2)
$14.4×25=360$
$1.44×25=36$
$0.144×25=3.6$
$2.5×144=360$
2. 用竖式计算。
0.75×18=
4.32×15=
1.05×28=
1.08×27=
3.65×21=
0.246×32=
0.75×18=
4.32×15=
1.05×28=
1.08×27=
3.65×21=
0.246×32=
答案
```
0.75
× 18
------
600
75
------
13.50
```
$0.75×18=13.5$
---
```
4.32
× 15
------
2160
432
------
64.80
```
$4.32×15=64.8$
---
```
1.05
× 28
------
840
210
------
29.40
```
$1.05×28=29.4$
---
```
1.08
× 27
------
756
216
------
29.16
```
$1.08×27=29.16$
---
```
3.65
× 21
------
365
730
------
76.65
```
$3.65×21=76.65$
---
```
0.246
× 32
-------
492
738
-------
7.872
```
$0.246×32=7.872$
0.75
× 18
------
600
75
------
13.50
```
$0.75×18=13.5$
---
```
4.32
× 15
------
2160
432
------
64.80
```
$4.32×15=64.8$
---
```
1.05
× 28
------
840
210
------
29.40
```
$1.05×28=29.4$
---
```
1.08
× 27
------
756
216
------
29.16
```
$1.08×27=29.16$
---
```
3.65
× 21
------
365
730
------
76.65
```
$3.65×21=76.65$
---
```
0.246
× 32
-------
492
738
-------
7.872
```
$0.246×32=7.872$
3. 看图写出乘法算式,再说说算式表示的含义。
(1)
(2) 每个大正方形表示1,阴影部分表示多少?
(1)
(2) 每个大正方形表示1,阴影部分表示多少?
答案
(1)
$4.5×3=13.5$(元)
算式含义:求3个4.5相加的和是多少。
(2)
$0.79×4=3.16$
算式含义:求4个0.79相加的和是多少。
答:3支单价为4.5元的笔总价是13.5元,所有阴影部分一共表示3.16。
$4.5×3=13.5$(元)
算式含义:求3个4.5相加的和是多少。
(2)
$0.79×4=3.16$
算式含义:求4个0.79相加的和是多少。
答:3支单价为4.5元的笔总价是13.5元,所有阴影部分一共表示3.16。
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