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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,*,复习旧知识,你是怎样算出15-9=?这个算式的得数的呢?,9+()=15,6,15-9=,6,16-9=,想:因为,9+7=16,,所以,16-9=7,7,做减想加,16-9=,6,7,1,10,破十法,13-9=15-9=17-9=,11-9=12-9=14-9=,16-9=18-9=19-9=,4,6,8,2,3,5,7,9,10,十几减九等于个位上的数几加上一,开火车啦!,15-9=,13-9=,17-9=,16-9=,18-9=,6,4,8,7,9,十几减8、7、6,20以内的退位减法,8+()=1,3,8+()=12,8+()=14 8+()=11,8+()=17 8+()=1,5,8+()=18 8+()=16,5,6,9,10,4,3,7,8,4,12-8=,4,还剩几个?,想:,10-8=,2,2+,2,=4,12-8 =4,2 10 2,破十法,12-8=,还剩几个?,8+()=12,4,12-8=,4,想加法算减法,想:,4,8,7,13,5,11,3,14,6,13,枝,?枝,13,8=,5,15,个,?个,15,8=,7,7+()=13 7+()=12,7+()=14 7+()=11,7+()=1,5,7+()=1,6,6+,(),=11 6+,(),=13,6+,(),=15 6+,(),=12,6,7,8,5,4,9,5,7,9,6,13-7=,13-6=,6,7,13-7=,想:,10-7=,3,3+,3,=6,6,想:,7+()=13,13-7=,6,6,1,3 -7 =6,3 10 3,13,6=,想:,10-6=,4,3+,4,=7,7,想:,6+()=13,13-6=,7,7,1,3 -6 =7,3 10 4,6,8,6,8,8,8,7,7,17,9,8,15,6,9,16,9,7,4,4,5,5,6,6,11,9=,12,9=,13,9=,14,9=,15,9=,16,9=,17,9=,18,9=,你发现了什么?,2,3,4,5,6,7,8,9,十几减,9,,是几加,1,11,8=,12,8=,13,8=,14,8=,15,8=,16,8=,17,8=,你发现了什么?,3,4,5,6,7,8,9,十几减,8,,是几加,2,11,7=,12,7=,13,7=,14,7=,15,7=,16,7=,你发现了什么?,4,5,6,7,8,9,十几减,7,,是几加,3,11,6=,12,6=,13,6=,14,6=,15,6=,你发现了什么?,5,6,7,8,9,十几减,6,,是几加,4,请大家谈谈今天的收获,今天我学习了,(,),,其中最喜欢的方法是(,),十几减,8,、,7,、,6,
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