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单击此处编辑母版标题样式,单击此处编辑母版文本样式,第二级,第三级,第四级,第五级,*,Click to edit Master title style,Click to edit Master text styles,Second level,Third level,Fourth level,Fifth level,*,2、5的倍数的特征,1、在2、3、5、8、10、12、25、40这几个数中,40的因数有几个?5的倍数有几个?,复习:,2、在6、10、12、15、18、20这几个数中,哪些数是2的倍数?哪些数是5的倍数?,40的因数有2,5,8,10,40。,5的倍数有5,10,25,40。,2的倍数有6,10,12,18,20。,5的倍数有10,15,20。,3245 2963 8037 7231 12035 4570,你能快速判断下面这几个数,哪几个是2的倍数?哪几个是5的倍数?,哪些号码是双号?,2,4,6,8,10,12,14,它们都是2的倍数。,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,2的倍数,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,2的倍数的特征,个位上是0、2、4、6、8的数,都是2的倍数。(也就是能被2整除的数),自然数中,是2的倍数的数叫做偶数(0也是偶数),不是2的倍数的数叫做奇数。,自然数,奇数,偶数,不能被2整除的数,个位上是1,3,5,7,9。,能被2整除的数,个位上是0,2,4,6,8。,最小的偶数是几?有没有最大的偶数?,最小的奇数是几?有没有最大的奇数?,最小的偶数是0,没有最大的偶数。,最小的奇数是1,没有最大的奇数。,考 考 你,给2的倍数涂上绿色。,19,104,36,65,48,153,287,78,104,36,48,78,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,5的倍数,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71,72,73,74,75,76,77,78,79,80,81,82,83,84,85,86,87,88,89,90,91,92,93,94,95,96,97,98,99,100,5的倍数的特征,个位上是0或5的数,都是5的倍数。(也就是能被5整除的数),2的倍数,24,,90,,60,,106,,130,,280。,5的倍数,35,,90,,15,,60,,75,,130,,280。,2的倍数,24,,106,,5的倍数,35,,90,,15,,60,,75,,130,,280。,60,,280。,90,,130,,既是2的倍数,又是5的倍数。,2和5的共同倍数的特征,个位上是”0”的自然数,既是5的倍数,又是2的倍数.,思考:,奇数+偶数=();,奇数+奇数=();,偶数+偶数=()。,奇 数,偶 数,偶 数,严谨认真,天天进步,
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