数学人教版四年级上册 第1课时 三位数乘两位数的笔算乘法

,第1课时三位数乘两位数的笔算乘法,R四年级上册,三位数乘两位数,【学习目标】,1.经历三位数乘两位数的笔算过程，体验类推迁移的思想方法，感受新旧知识的联系。,2.经历与他人交流笔算的过程，激发学生学习数学的兴趣，培养学生自主探索、合作交流的习惯。,3.感受数学在生活中的应用及数学与生活的密切联系。,【学习重点】,【学习难点】,掌握三位数乘两位数的笔算方法。,理解竖式中，第二个因数的十位与第一个因数相乘时，积的末尾要与十位对齐的道理。,一、新课导入,口算,2330,4720,4219,5841,690,940,800,2400,计算,1118,408,4326,1234,二、探索新知,李叔叔从某城市乘火车去北京用了12小时，火车每小时行145千米。该城市到北京有多少千米？,14512,我是这样想的：估计约有1500千米。14512150015010,14512,145,0,5,1,4,2,9,0,1,7,4,用笔算比较准确，得,1740,笔算对了吗？用计算器验算一下。,做一做,134,12,8,6,2,4,3,1,0,8,6,1,176,47,2,3,12,4,0,7,7,2,2,8,425,36,0,5,25,5,7,12,0,0,3,5,1,237,82,4,7,4,6,9,18,3,4,4,9,1,322,24,8,8,12,4,4,6,2,8,7,7,145,27,5,1,10,0,9,2,1,5,9,3,679,13,7,3,20,9,7,6,2,7,8,8,286,35,0,3,14,8,5,8,1,0,0,10,三、巩固提高,1.口算。,1320=243=5080=1504=1840=9120=,260,72,4000,720,1080,600,2.笔算。,3723=3425=,37,23,1,11,4,7,5,1,8,851,34,25,0,7,1,8,6,5,0,8,850,6014=4532=,14,60,4,8,0,45,32,0,9,5,3,4,0,4,1,1,840,1440,1722=8470=,17,22,4,3,4,3,7,4,3,374,84,70,8,58,0,5880,3.估算。,792029110239992859,16000,9000,4000,1800,4.先用竖式计算，再用计算器验算。,27325=67124=,273,25,5,6,13,6,4,5,2,5,8,6,6825,124,67,8,6,8,4,4,7,0,8,3,8,8308,35321=63812=,321,35,5,0,16,3,6,9,3,5,2,11,11235,638,12,6,7,12,8,3,6,5,6,6,7,7656,5.改正下题中的错误。,215,45,5,7,10,6,8,3,5,9,1,0,改正,215,5,7,10,6,8,7,5,6,9,0,45,6.学校为同学们定制校服。每套89元，买了514套这样的校服，一共要花多少钱？,89514=45746（元）,答：一共要花45746元钱。,7.计算。,157,24,8,2,6,4,1,6,8,7,3,3,259,43,7,7,7,6,3,3,7,1,1,10,1,四、课堂小结,三位数乘两位的笔算乘法,145,0,5,1,4,2,9,0,1,7,4,1452=290,14510=1450,290+1450=174