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1、整数的四则运算,黄浦区蓬莱路第二小学 赵英,用这7个数,编几道不同运算的一步口算题。,25 164 100 32 4 2 64,(164 25 4) 32, 32 = 2,25 4 =,100,164-,100,=,64,64,四则运算要注意,明确顺序是关键。,同级运算最好办,,两级运算都出现,,顺序不乱再检验,又对又快喜心间。,遇到括号怎么办?,四则运算歌,42725,10125-2125,4+2725,10(125-2)125,= 42527= 10027= 2700,=(10-2)125= 8125= 1000,= 4 +675= 679,= 10123125= 1230125= 153
2、750,42725,10125-2125,4+2725,10(125-2)125,= 42527= 10027= 2700,=(10-2)125= 8125= 1000,= 4 +675 = 679,= 10123125= 1230125= 153750,= 27 (425)= 27 100= 2700,42725,10125-2125,= 42527= 10027= 2700,=(10-2)125= 8125= 1000,42725 = 27 (425)= 27 100= 2700,42725,10125-2125,4+2725,10(125-2)125,= 42527= 10027= 27
3、00,=(10-2)125= 8125= 1000,= 4 +675= 679,= 10123125= 1230125= 153750,运算魔法空间,翻,翻,乐,辨一辩,说一说,算一算,135+45+265+455=(135+265)+(45+455)= 400+500= 900,=(69-1+32)31 = 10031 = 3100,6931-31+3231,= 6931-131+3231,375375 = 185185 = 1,( ),(),( ),辨一辩,99102,125888,算一算,99102,= 99(100+2) = 99100+992 = 9900+198 = 10098,99102,=(100-1)102 = 100102-1102 = 10200-102 = 10098,算一算,125888,= 125 (800+80+8)= 125 800+125 80+125 8= 100000+10000+1000= 111000,算一算,125888,= 125(8111)= 1258111= 1000111= 111000,480048-242,4800(48-24)2 ,说一说,2,?,破解线索,3,4,妙,解,诗,妙解诗,李白街上走,提壶去买酒;遇店加一斗,见花喝一半;三遇店和花,壶中剩一斗;请你算一算,原有酒几斗?,