单击此处编辑母版标题样式,单击此处编辑母版文本样式,二级,三级,四级,五级,2024/9/26,#,人教版数学一年级（上）,20,以内的进位加法,第,4,课时,5,、,4,、,3,、,2,加几,1,.,掌握,5,、,4,、,3,、,2,加几可以用“凑十法”和交换加数的方法进行计算。,2,.,经历探究,5,、,4,、,3,、,2,加几的计算方法的过程,，提高知识迁移、类推能力,。,3,.,养成良好的书写习惯和认真负责的态度。,学习目标,【,难点,】,联系学过的相应的加法算式，直接算出得数。,【,重点,】,掌握用交换加数位置的方法计算,5,、,4,、,3,、,2,加几,的加法,。,口算。,知识回顾,9,+,5=,14,8,+,5=,13,7,+,5=,12,6,+,5=,11,观察这四个算式有什么相同的地方？,14,13,12,11,6,+,5=,5,9,+,5=,8,+,5=,7,+,5=,13,12,11,2,.,这四个算式的第二个加数都是,5,，是几加,5,的算式。,5,5,5,1,.,这四个算式的第一个加数是,9,、,8,、,7,、,6,，是,9,、,8,、,7,、,6,加几的算式,。,14,口算。,把这组算式变型，交换加数的位置。,5,+,9=,5,+,8=,5,+,7=,5,+,6=,6,+,5=,9,+,5=,8,+,5=,7,+,5=,13,12,11,14,5,+,8 =,5,+,8 =,5,+,8 =,新知探究,5,+,8 =,13,3,5,10,教科书第,93,页例,4,13,3,2,10,4,你是怎么计算的？,“拆大数,、,凑小数”,我用凑十法,“拆小数,、,凑大数”,5,+,8 =,5,13,教科书第,93,页例,4,我利用交换加数的位置和不变的规律,8 +5 =,5,+,8 =,8,13,13,4,9+2=,8+3=,9+4=,9+5=,4,5,+,9=,5,14,14,9,4,+,9=,13,13,9,3,+,8=,3,11,11,8,2,+,9=,2,11,11,9,你发现了什么？,用交换,加数的,位置的方法可以很快地算出得数。,试一试,5,加几,还有哪些,5,加几的进位加法算式呢？,5,+,9 =,14,5,+,=,5,+,=,读一读这几个算式,你有什么新发现吗？,第二个算式从,9,开,5,+,=,8,13,7,12,6,11,的得数也依次小,1,，,而且都是十几，是,有规律的。,始依次小,1,，,它们,我发现：,课堂练习,做一做。,教科书第,93,页,做一做,3,+,9=,8=,4,+,9=,8=,7=,5,+,9=,8=,7=,6=,11,12,11,12,13,11,12,13,14,1,.,填一填。,4,教科书第,94,页,练一练,2.,移动,8,，每次用,8,加上方格里的数。,8,0,2,7,5,8,3,10,6,9,8,+,4 =12,8,+,0 =,8,8,+,2 =,10,8,+,7 =,15,8,+,5 =,13,8,+,8 =16,8,+,3 =11,8,+,10=,18,8,+,6 =,14,8,+,9 =,17,教科书第,94,页,练一练,3,4,0,2,7,5,8,3,10,6,9,3,+,4 =7,3,+,0 =,3,3,+,2 =,5,3,+,7 =,10,3,+,5 =,8,3,+,8 =11,3,+,3 =6,3,+,10=,13,3,+,6 =,9,3,+,9 =,12,2.,把,8,换成,3,，再加一加,。,教科书第,94,页,练一练,4,4,0,2,7,5,8,3,10,6,9,4,+,4 =,8,4,+,0 =,4,4,+,2 =,6,4,+,7 =,11,4,+,5 =,9,4,+,8 =12,4,+,3 =7,4,+,10=,14,4,+,6 =,10,4,+,9 =,13,2.,把,8,换成,4,，再加一加,。,教科书第,94,页,练一练,5,4,0,2,7,5,8,3,10,6,9,5,+,4 =,9,5,+,0 =,5,5,+,2 =,7,5,+,7 =,12,5,+,5 =,10,5,+,8 =13,5,+,3 =8,5,+,10=,15,5,+,6 =,11,5,+,9 =,14,2.,把,8,换成,5,，再加一加,。,4+7=,11,13,你发现了什么？,教科书第,95,页,练一练,观察这行算式可以发现每个算式的第一个的加,数是从,4,开始依次多,1,，第二个加数都是,7,，因此,5+6=,1,1,1,2,5+7=,5+8=,1,3,6+7=,它们的和也依次多,1,。,观察这列算式可以发现每个算式的第一个的加,数都是,5,，第二个加数是从,6,开始依次,多,1,，因此,它们的和也依次多,1,。,3.,想一想，填一填,。,=,观察发现左边有,2,个图形，右边有,9,个图形，一共有多少的图形，用加法计算。,2,+,9,11,4.,看图计算,。,7+6,9+6,4+9,4+8,8+7,5+7,5+8,6+6,15,12,13,5.,把得数是,15,、,13,、,12,的算式写在相应方框里,。,课堂小结,5,、,4,、,3,、,2,加几,凑十法,交换加数的位置,作业课件中的相关练习。,02,01,课后练一练第,2-5,题。,