201X春五年級數(shù)學(xué)下冊 2《因數(shù)與倍數(shù)》解決問題課件 （新版）新人教版

1、因數(shù)與倍數(shù)因數(shù)與倍數(shù)解決問題把下面各數(shù)分別填在合適的圈內(nèi)。把下面各數(shù)分別填在合適的圈內(nèi)。39 48 51 207 420 801 8976奇數(shù)奇數(shù)偶數(shù)偶數(shù)513920780148420 8976說說你是怎么判斷的？說說你是怎么判斷的？在整數(shù)中，是在整數(shù)中，是2的倍數(shù)的的倍數(shù)的數(shù)就是偶數(shù)，否則就是數(shù)就是偶數(shù)，否則就是奇數(shù)。奇數(shù)。個位上是個位上是0、2、4、6、8的數(shù)是偶數(shù)；個位上是的數(shù)是偶數(shù)；個位上是1、3、5、7、9的數(shù)是的數(shù)是奇數(shù)。奇數(shù)。奇數(shù)與偶數(shù)的和是奇數(shù)還是偶數(shù)？奇數(shù)與奇數(shù)的和奇數(shù)與偶數(shù)的和是奇數(shù)還是偶數(shù)？奇數(shù)與奇數(shù)的和是奇數(shù)還是偶數(shù)？偶數(shù)與偶數(shù)的和呢？是奇數(shù)還是偶數(shù)？偶數(shù)與偶數(shù)的和呢？

2、奇數(shù)奇數(shù)偶數(shù)偶數(shù)奇數(shù)奇數(shù)? ?偶數(shù)？偶數(shù)？奇數(shù)奇數(shù)奇數(shù)奇數(shù)奇數(shù)？奇數(shù)？偶數(shù)？偶數(shù)？偶數(shù)偶數(shù)偶數(shù)偶數(shù)奇數(shù)？奇數(shù)？偶數(shù)？偶數(shù)？從題目中你知道了什么？從題目中你知道了什么？閱讀與理解閱讀與理解題目讓我們對奇題目讓我們對奇數(shù)、偶數(shù)的和做數(shù)、偶數(shù)的和做一些探索。一些探索。我把問題表示我把問題表示成這樣成這樣我隨便找?guī)讉€奇數(shù)、偶我隨便找?guī)讉€奇數(shù)、偶數(shù)，加起來看一看。數(shù)，加起來看一看。奇數(shù)：奇數(shù)：5， 7， 9， 11，偶數(shù)：偶數(shù)：8，12，20，24，571279165813781581220122436奇數(shù)奇數(shù)奇數(shù)奇數(shù)偶數(shù)偶數(shù)奇數(shù)奇數(shù)偶數(shù)偶數(shù)奇數(shù)奇數(shù)偶數(shù)偶數(shù)偶數(shù)偶數(shù)偶數(shù)偶數(shù)奇數(shù)與偶數(shù)的和是奇數(shù)還是偶數(shù)？

3、奇數(shù)與奇數(shù)的和奇數(shù)與偶數(shù)的和是奇數(shù)還是偶數(shù)？奇數(shù)與奇數(shù)的和是奇數(shù)還是偶數(shù)？偶數(shù)與偶數(shù)的和呢？是奇數(shù)還是偶數(shù)？偶數(shù)與偶數(shù)的和呢？你怎么想？你怎么想？分析與解答分析與解答奇數(shù)除以奇數(shù)除以2余余1奇數(shù)：奇數(shù)：偶數(shù)：偶數(shù)：偶數(shù)除以偶數(shù)除以2沒有余數(shù)沒有余數(shù)奇數(shù)加偶數(shù)的和除以奇數(shù)加偶數(shù)的和除以2還余還余1，所以，奇數(shù)，所以，奇數(shù)偶數(shù)偶數(shù)奇數(shù)。奇數(shù)。奇數(shù)加奇數(shù)的和除以奇數(shù)加奇數(shù)的和除以2沒有余數(shù)，所以，奇數(shù)沒有余數(shù)，所以，奇數(shù)奇數(shù)奇數(shù)偶數(shù)。偶數(shù)。偶數(shù)加偶數(shù)的和除以偶數(shù)加偶數(shù)的和除以2沒有余數(shù)，所以，偶數(shù)沒有余數(shù)，所以，偶數(shù)偶數(shù)偶數(shù)偶數(shù)。偶數(shù)。奇數(shù)與偶數(shù)的和是奇數(shù)還是偶數(shù)？奇數(shù)與奇數(shù)的和奇數(shù)與偶數(shù)的和是奇數(shù)

4、還是偶數(shù)？奇數(shù)與奇數(shù)的和是奇數(shù)還是偶數(shù)？偶數(shù)與偶數(shù)的和呢？是奇數(shù)還是偶數(shù)？偶數(shù)與偶數(shù)的和呢？你怎么想？你怎么想？分析與解答分析與解答奇數(shù)與偶數(shù)的和是奇數(shù)還是偶數(shù)？奇數(shù)與奇數(shù)的和奇數(shù)與偶數(shù)的和是奇數(shù)還是偶數(shù)？奇數(shù)與奇數(shù)的和是奇數(shù)還是偶數(shù)？偶數(shù)與偶數(shù)的和呢？是奇數(shù)還是偶數(shù)？偶數(shù)與偶數(shù)的和呢？奇數(shù)奇數(shù)奇數(shù)奇數(shù)奇數(shù)奇數(shù)偶數(shù)偶數(shù)偶數(shù)偶數(shù)偶數(shù)偶數(shù)偶數(shù)偶數(shù)奇數(shù)奇數(shù)偶數(shù)偶數(shù)所以，你們的所以，你們的結(jié)論是結(jié)論是奇數(shù)與偶數(shù)的和是奇數(shù)還是偶數(shù)？奇數(shù)與奇數(shù)的和奇數(shù)與偶數(shù)的和是奇數(shù)還是偶數(shù)？奇數(shù)與奇數(shù)的和是奇數(shù)還是偶數(shù)？偶數(shù)與偶數(shù)的和呢？是奇數(shù)還是偶數(shù)？偶數(shù)與偶數(shù)的和呢？534319853所以，奇數(shù)所以，奇數(shù)偶數(shù)偶數(shù)奇

5、數(shù)奇數(shù)回顧與反思回顧與反思這個結(jié)論正確嗎？這個結(jié)論正確嗎？我可以再找一些我可以再找一些大數(shù)試一試。大數(shù)試一試。同學(xué)們還有其他方法嗎？同學(xué)們還有其他方法嗎？你覺得哪種方法好？你覺得哪種方法好？1.30個學(xué)生要分成甲、乙兩隊。如果甲隊人數(shù)為奇數(shù)，乙隊個學(xué)生要分成甲、乙兩隊。如果甲隊人數(shù)為奇數(shù)，乙隊人數(shù)為奇數(shù)還是偶數(shù)？如果甲隊人數(shù)為偶數(shù)呢？人數(shù)為奇數(shù)還是偶數(shù)？如果甲隊人數(shù)為偶數(shù)呢？30是偶數(shù)，甲隊人數(shù)為奇是偶數(shù)，甲隊人數(shù)為奇數(shù)，奇數(shù)奇數(shù)偶數(shù)，數(shù)，奇數(shù)奇數(shù)偶數(shù)，所以，乙隊人數(shù)是奇數(shù)。所以，乙隊人數(shù)是奇數(shù)。30是偶數(shù)，甲隊人數(shù)是偶數(shù)，甲隊人數(shù)是偶數(shù)，偶數(shù)偶數(shù)是偶數(shù)，偶數(shù)偶數(shù)偶數(shù)，所以，乙隊偶數(shù)，所以，乙隊人數(shù)是偶數(shù)。人數(shù)是偶數(shù)。2. 奇數(shù)與奇數(shù)的積是奇數(shù)還是偶數(shù)？奇數(shù)與偶數(shù)的奇數(shù)與奇數(shù)的積是奇數(shù)還是偶數(shù)？奇數(shù)與偶數(shù)的 積是奇數(shù)還是偶數(shù)？偶數(shù)與偶數(shù)的積呢？積是奇數(shù)還是偶數(shù)？偶數(shù)與偶數(shù)的積呢？5735796