减法的性质练习课ppt课件.pptx

看看谁课前准备做得好！1.请准备好笔和练习本。2.请将听课设备的音量调到适合的位置。3.为了正常上课，请尽量一个学生只是用一个设备上课哟，那样就不会“堵车”了！谢谢配合！,在连减算式中，可以根据实际情况，选择合适的计算方法：,2.一个数连续减去几个数等于减去这几个数的和。,3.如减数和被减数有相同部分，可以交换减数的位置。,1.从左往右按顺序计算。,用字母表示为：a-b-c=a-(b+c),a-b-c=a-c-b,射击游戏,看看哪个方法最好.,800138162（）,A,800138162=662162=500,B,800138162=800（138162）=800300=500,看看哪个方法最好.,47249272（）,A,B,47249272=472（49272）=472321=151,47249272=47227249=20049=151,射击游戏,1445644=8844=132,947(47800)=94747800=900800=100,651481151=651151481=500481=19,a-b-c=a-(b+c),a-(b+c)=a-b-c,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,2.计算下面各题，怎样简便就怎样计算。487-187-139-61 169-25-25-50,=487-187-（139+61）=487-187-200=300-200=100,=169-（25+25+50）=169-100=69,3、计算下面各题，怎样简便就怎样计算。,470-254-46,579-（79+123）,=470-(254+46),=470-300,=170,=579-79-123,=500-123,=377,545-167-145,=545-145-167,=400-167,=233,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,状元成才路,20004162842000（416284）20007001300（m）答：海拔1300m。,5、共计有效票325张。其中赞成276票，反对24票，弃权_票。,325-276-24,再见，优秀的孩子们！,再见，优秀的孩子们！,再见，优秀的孩子们！,