数学三年级下册一 两位数乘两位数教学演示ppt课件

这是一份数学三年级下册一 两位数乘两位数教学演示ppt课件，共15页。PPT课件主要包含了X10110，一共有多少个，个24，×2的积，×10的积，可以用竖式计算，个位上的0可以不写，一般写成这样的形式等内容，欢迎下载使用。
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幼儿园购进12箱迷你南瓜，每箱24个。
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2 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●
3 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●
4 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●
5 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●
6 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●
7 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●
8 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●
9 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●
10 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●
11 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●
12 ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ● ●
方法一： 2×6=12 先把24×12变成24×2×6
24×2=48,48×6=288
方法二：12箱可以分成2箱和10箱。 24×2=48（个） 24×10=240（个） 48+240=288(个）
2 8 8
2.列竖式计算，并验算：
学校买21个热水瓶，每个23元。根据下面的竖式，在（ ）里填合适的数。
2 3Χ 2 1 2 3 …买（ ）个热水瓶应付（ ）元4 6 …买（ ）个热水瓶应付（ ）元4 8 3 …买（ ）个热水瓶应付（ ）元
14×21＝42 1 4 ×2 1
14×21＝ 1 4 × 2 1
32×23＝294 3 1 ×2 3
32×23＝ 3 2 ×2 3