单击此处编辑母版标题样式,编辑母版文本样式,第二级,第三级,第四级,第五级,2017/1/9,#,寻找规律,上课老师:陈婷婷,1,、数出下图有几个正方形?,知识点及作业回顾:,2,、有,16,六个数字,这些数,字能组成多少个个位上的,数字与十位上的数字不同,的两位数?,寻找宝藏的密码,小朋友你能帮他破解密码吗?,1,,,3,,,7,,,15,,(),,63,,,127,?,例,1,:先找出下列数排列的规律,并根据规律在括号里填上适当的数。,3,,,6,,,9,,,12,,(),,18,,,1,,,2,,,4,,,7,,,11,,(),(),,1,,,2,,,4,,,8,,(),(),,64,,,3,,,6,,,9,,,12,,(),,18,,,相邻两个数的差都是,3,,根据这一规律,括号里应填的数为:,12+3=15,或,18-3=15,15,1,,,2,,,4,,,7,,,11,,(),(),,第,2,个数比第,1,个数增加,1,,第,3,个数比第,2,个数增加,2,,,第,4,个数比第,3,个数增加,3,根据这一规律,括号里应,填的两个数分别为:,11+5=16,和,16+6=22,1,,,2,,,3,,,4,,,5,,,6,,,16,22,1,,,2,,,4,,,8,,(),(),,64,,,16,32,等差数列:一般地,如果一个数列从第2项起,每一项与它的前一项的差等于同一个常数,那么这个数列就叫做等差数列。,等比数列:如果一个数列从第,2,项起,每一项与它的前一项的比值(商)等于同一个常数,那么这个数列就叫做等比数列。,简单认识等差数列和等比数列,3,,,6,,,9,,,12,,(,15,),,18,,,1,,,2,,,4,,,8,,(,16,),(,32,),,64,,,我们来对比一下等差数列跟等比数列的变化情况,3,,,6,,,9,,,12,,(,15,),,18,,,变化,缓慢,,用加减法。,1,,,2,,,4,,,8,,(,16,),(,32,),,64,,,变化,剧烈,,用乘除法。,练习,1,:先找出下列数排列的规律,并根据规律在括号里填上适当的数。,2,,,4,,,8,,,10,,(),(),,2,,,5,,,8,,,11,,(),,17,,,20,,,33,,,28,,,23,,(),,13,,(),,3,,,55,,,49,,,43,,(),,31,,(),,19,,,练习,1,:先找出下列数排列的规律,并根据规律在括号里填上适当的数。,2,,,4,,,8,,,10,,(,12,),(,14,),,2,,,5,,,8,,,11,,(,14,),,17,,,20,,,33,,,28,,,23,,(,18,),,13,,(,8,),,3,,,55,,,49,,,43,,(,37,),,31,,(,25,),,19,,,变化缓慢,用加减法,练习,2,:先找出下列数排列的规律,并根据规律在括号里填上适当的数。,3,,,5,,,12,,(,),,48,,(),,2,,,6,,,18,,(,),,162,,,486,,,128,,,64,,,32,,(,),,8,,(,),,768,,(,),,48,,,12,,,3,,,练习,2,:先找出下列数排列的规律,并根据规律在括号里填上适当的数。,3,,,5,,,12,,(,24,),,48,,(,96,),,2,,,6,,,18,,(,54,),,162,,,486,,,128,,,64,,,32,,(,16,),,8,,(,4,),,768,,(,192,),,48,,,12,,,3,,,变化剧烈,用乘除法,例,2,:先找出下列数排列的规律,并根据规律在括号里填上适当的数。,(,1,),15,,,2,,,12,,,2,,,9,,,2,,(),(),(,2,),21,,,4,,,18,,,5,,,15,,,6,,(),(),例,3,:根据前面图形里的数的排列规律,填入适当的数。,5,10,9,14,7,12,11,16,9,14,13,?,例,3,:根据前面图形里的数的排列规律,填入适当的数。,5,10,9,14,7,12,11,16,9,14,13,18,还有其他规律吗?,5,5,5,加强版(隐藏很深的规律),4,16,8,2,7,14,8,4,9,4,3,加强版(隐藏很深的规律),4,16,8,2,7,14,8,4,9,4,3,12,培优升级,例,4,:按规律填数,(,1,),187,,,286,,,385,,(),(),(,2,),23,31,2541,41,23,4643,35,24,?,培优升级,例,4,:按规律填数,(,1,),187,,,286,,,385,,(,?,),(,?,),思维导航:,留意每个数的个位、十位、百位。,百位以此增加(,?,),各位以此减少(,?,),十位,(?),。,培优升级,例,4,:按规律填数,(,1,),187,,,286,,,385,,(,484,),(,583,),思维导航:,留意每个数的个位、十位、百位。,百位以此增加(,1,),各位以此减少(,1,),十位不变。,培优升级,例,4,:按规律填数,(,2,),23,31,2541,41,23,4643,35,24,?,思维导航:,上方两个数的左边数的十位和右边数的个位分别组成了下方数字,的首尾与末尾,那么下方数字中间的两个数是由什么规律组成的,呢?,培优升级,例,4,:按规律填数,(,2,),23,31,2541,41,23,4643,35,24,3594,思维导航:,上方两个数的左边数的十位和右边数的个位分别组成了下方数字,的首尾与末尾,那么下方数字中间的两个数是由上方两个数的十,位相加和个位相加组成。,1,,,3,,,7,,,15,,(),,63,,,127,?,你学会了吗?,再见,课后作业:,按规律填数,2,,,5,,,14,,,41,,(),252,,,124,,,60,,,28,,(),9,12,36,12,4,3,27,36,