五年級(jí)下冊(cè)數(shù)學(xué)課件-1-5倍數(shù)與因數(shù)整理與復(fù)習(xí)-西師大版共14張PPT[文字可編輯]

1、西南師大版五年級(jí)數(shù)學(xué)（下）第一章,倍,數(shù),與,因,數(shù),整理與復(fù)習(xí),一個(gè)小游戲,1,只青蛙,1,張嘴,2,只眼睛,4,條腿,說(shuō)一說(shuō),2,只青蛙,2,張嘴,4,只眼睛,8,條腿,紅色數(shù)字包含哪,3,只青蛙,3,張嘴,6,只眼睛,12,條腿,些數(shù)學(xué)信息,4,只青蛙,4,張嘴,8,只眼睛,16,條腿,80,條腿,40,只眼睛,20,張嘴，,20,只青蛙,100,張嘴，,200,只眼睛,400,條腿,100,只青蛙,1000,只青蛙,1000,張嘴，,2000,只眼睛,4000,條腿,知識(shí)回顧,質(zhì)數(shù),因,因數(shù),數(shù),合數(shù),與,公因數(shù),奇數(shù),倍,公倍數(shù),2,的倍數(shù)特征,數(shù),偶數(shù),倍數(shù),3,的倍數(shù)特征,5,的

2、倍數(shù)特征,自然數(shù),質(zhì)數(shù),奇數(shù),自,自,然,然,數(shù),1,數(shù),合數(shù),偶數(shù),定義,自然數(shù),0,1,2,3,4,5,6,倍數(shù)與因數(shù),將一個(gè)數(shù)寫(xiě)成另外兩個(gè)數(shù)乘積的形式，就說(shuō),這個(gè)數(shù)是這兩個(gè)數(shù)的倍數(shù)，這兩個(gè)數(shù)是這個(gè)數(shù)的因數(shù),2,3=6,2,和,3,是因數(shù),6,是倍數(shù),32,4=8,2,3,是,6,的因數(shù),6,是,2,和,3,的倍數(shù),4,8,是,32,的因數(shù),32,是,4,和,8,的倍數(shù),說(shuō)出下面各數(shù)的因數(shù),注：別忘了本身,1,1,2,4,1,4,2,1,2,15,3,5,1,17,1,9,3,15,1,9,17,特點(diǎn),都有,1,和它本身,2,每個(gè)數(shù)的最大因數(shù)是它本身,1,1,分類(lèi),2,17,4,9,15,

3、只有,1,個(gè)因數(shù),既不是質(zhì)數(shù)也不是合數(shù),質(zhì)數(shù),合數(shù),自,然,數(shù),只有,1,和它本身,2,個(gè)因數(shù),3,個(gè)以上因數(shù)（除,1,和它本身外還有其他因數(shù),1,3,既是,9,的因數(shù),又是,15,的因數(shù),3,最大,9,的因數(shù),1,3,9,15,的因數(shù),1,15,3,5,公因數(shù),最大公因數(shù),求,14,和,28,的最大公因數(shù),短除法,2,7,14 28,7 14,1 2,14,和,28,的最大公因數(shù),2,7=14,說(shuō)出下面各數(shù)的倍數(shù),注：別忘了本身,2,4,6,8,10,12,14,16,18,20,22,24,2,的倍數(shù),3,6,9,12,15,18,21,24,27,30,33,3,的倍數(shù),5,10,15,

4、20,25,30,35,40,45,50,5,的倍數(shù),自,找一找,然,數(shù),個(gè)位上是,0,2,4,6,8,的數(shù),偶數(shù),2,的倍數(shù)特點(diǎn),各數(shù)位上數(shù)字之和是,3,的倍數(shù),3,的倍數(shù)特點(diǎn),個(gè)位上是,0,或,5,的數(shù),5,的倍數(shù)特點(diǎn),個(gè)位上是,1,3,5,7,9,的數(shù),奇數(shù),任何數(shù)的倍數(shù)都,包含它本身,本身最小，最大,不存在,試一試,關(guān)于奇數(shù)與偶數(shù),如果用,a,來(lái)表示任意一個(gè)自然數(shù)，那么,偶數(shù)可以表示為,2a,奇數(shù)可以表示為,2a+1,奇數(shù),奇數(shù),偶數(shù),偶數(shù),偶數(shù),偶數(shù),奇數(shù),偶數(shù),奇數(shù),奇數(shù)奇數(shù),奇數(shù),偶數(shù)偶數(shù),偶數(shù),奇數(shù)偶數(shù),偶數(shù),相同為偶，不同為奇,同奇為奇，同偶為偶，有奇有偶則為偶,說(shuō)出下面各數(shù)

5、的倍數(shù),注：別忘了本身,2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,2,的倍數(shù),3,6,9,12,15,18,21,24,27,30,33,3,的倍數(shù),5,10,15,20,25,30,35,40,45,50,5,的倍數(shù),找一找,6,12,18,24,既是,2,的倍數(shù)，又是,3,的倍數(shù),10,20,30,既是,2,的倍數(shù)，又是,5,的倍數(shù),公,倍,15,30,既是,3,的倍數(shù)，又是,5,的倍數(shù),數(shù),30,既是,2,的倍數(shù)，又是,3,的倍數(shù)，同時(shí)還是,5,的倍數(shù),最小公倍,數(shù)，不存,在最大公,倍數(shù),求,14,和,28,的最小公倍數(shù),2,短除法,14 28,7

6、,7 14,1 2,14,和,28,的最小公倍數(shù),2,7,1,2=28,回憶,求,14,和,28,的最大公因數(shù),2,短除法,14 28,7,7 14,1 2,14,和,28,的最大公因數(shù),2,7=14,總結(jié),如果一個(gè)數(shù),a,是另一個(gè)數(shù),b,的倍數(shù)，那么,b,就是這兩個(gè)數(shù)的最,大公因數(shù),a,是這兩個(gè)數(shù)的最小公倍數(shù),練一練,求下面各組數(shù)的最大公因數(shù)和最小公倍數(shù),6,和,8 40,和,30 12,和,24,2,6 8,3 4,5,2,40 30,8 6,4 3,2,2,3,12 24,6 12,3 6,1 2,6,和,8,的最大公因,2,數(shù)是,最小公倍數(shù)是,2,3,4=24,40,和,30,的最大公因,5,2=10,數(shù)是,最小公倍數(shù)是,5,2,4,3=120,12,和,24,的最大公因數(shù)是,2,2,3=12,最小公倍數(shù)是,2,2,3,1,2=24,試一試,求,12,18,和,24,的最大公因數(shù)和最小公倍數(shù),試一試,回顧總結(jié),1,因?yàn)?3,5=15,所以,15,是倍數(shù),3,5,是因數(shù)。,2,1,是所有非零自然數(shù)的因數(shù)。,3,任意一個(gè)數(shù)，它的因數(shù)是有限的