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题目要求用32.12

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乘以0.5

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小数相乘的时候

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跟整数相乘的方法

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是一样的

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然后数一数两个小数

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的小数部分

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加起来有几位

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得数就有几位小数

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下面我来给大家示范一下

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这两个数要相乘

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32.12乘以0.5

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写算式的时候

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右边对齐即可

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小数点这时候可以先忽略

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该写在哪就写在哪

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可以看成是3212乘以5

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小数点的问题算完再说

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下面来算一下

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5乘以3212的话

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5・2=10

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进1

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5・1=5 5+1=6

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5・2=10

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进1

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最后5・3=15 15+1=16

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这样就乘完了

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这个数看成05的话

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0就不用乘了

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乘也会得到0

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5乘以3212就得到这个数

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下面来看小数的问题

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数一数两个乘数一共有几位小数

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小数点后

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一共有几位

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1 2 3 有3位

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两个数小数点后

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一共有3位小数

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所以最后的答案

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也要有三位小数

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从右向左1 2 3 小数点在这里

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所以32.12乘以0.5得16.060

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最后这个0也可以不要

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并不改变小数的值

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可以写成16.06

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那么最后还要检查一下

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是不是做的对

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上边这个数大约是32

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乘以0.5

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0.5就是5/10

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也就是1/2

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所以实际上是32.12乘以1/2

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就是求32.12的一半是多少

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32的一半是16 0.12的一半是0.06

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结果非常正确