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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,*,两位数减一位数退位减法,一、口算,112,138,179,145,157,123,168,137,9,5,8,9,8,9,8,6,二、算一算,并说说你是怎样想的。,273,954,666,24,91,60,想:734,42024,想:541,19091,想:660,06060,368,答:还要再攒28元。,28元,练习,解答,368,6减8不够减怎么办?,翻开一捆再减。,28,还有什么方法吗?,368,368,20,16,8,26,10,2,28,28,返回,做一做,32,5,46,9,57,8,2,7,3,7,4,9,当当小老师,改改作业。,73974 ,68553 ,85773 ,算算我能行,。,7,6,4,5,7,3,6,7,5,3,2,5,4,6,9,5,7,8,7,2,5,4,6,2,2,7,3,7,4,9,十位数不变,不退位减法,十位数减少了一个十,退位减法,24,6,40 9 54 7,63 8 81 4 60 3,18,55,31,77,57,47,13,24,40,5,25,37,50,9,8,19,35,16,28,41,1湖边有22只船,划走7只。还剩几只?,2有48位家长来开会,已经搬了30把椅子。还缺多少把椅子?,22-7=15只,答:还剩15只。,48-30=18把,答:还缺18把椅子。,
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