小数点的移动和单位换算.ppt

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1、,小数移动与单位换算,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,例1:把0.07分别扩大到原来的10倍、100倍、1000倍，各是多少？,0.0710,0.7,7,70,【一题导解】,0.07100,0.071000,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

2、成才路,状元成才路,状元成才路,例2：把3.2分别缩小到原来的，各是多少？,0.32,0.032,0.0032,【一题导解】,1米=100厘米 100+45=145厘米,95,状元成才路,状元成才路,3、填一填,0.95米（）厘米,0.95100=95厘米,3千克=()吨,31000=0.003吨,1米45厘米（）厘米,0.003,145,【一题导解】,【一题导学】,（扩大到倍）,（缩小到几份之一）,小数点，本领大，走一走，数变化。右走扩大用乘法，左走缩小用除法。移动缺位也不怕，快用“0”来补足它。,口诀：,一想：（单位间的进率是多少）,二看：（大化小还是小化大）,三算：（大化小乘以进率，小数

3、点右移；小化大除以进率，小数点左移）,单位换算方法：,【一题导学】,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,状元成才路,状元成才路,0,2 9 6,例1：在括号里填上合适的数。,2.96,(),(),(296

4、),2 9 6,.,29.6,2 9 6,.,0,0.296,小数点向右移动位,小数点向左移动位,小数点向右移动位,一,两,三,.,【一题导学】,例2：我最棒，直接填得数。2.8710=3.91000=34.8110=21000=0.6710010=12.5100 1000=,0.002,3900,3.481,28.7,0.067,1.25,【一题导学】,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

5、元成才路,状元成才路,状元成才路,状元成才路,例3：乐乐饰品店购进10个海宝玩具共花了45.5元，如果再购进1000个这样的玩具，需要多少钱？,答：需要45500元。,45.5 X（100010）=45500（元）,45.5 10 X 1000=45500（元）,【一题导练】,300,86,例4：做一做，并说说改写方法。,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,6.32,8.035,0.43,5.6,0.3kg()g 0.86m2()dm26320米=()

6、千米 8035千克=()吨4角3分=()元 5米6分米=()米,【一题导练】,例5：判断。(对的打“”，错的打“”),(2)把千克数改写成吨数，要除以1000。(),(3)因为580克=0.58千克，所以6千克580克就等于60.58千克。(),(1)教室面积是56.8平方分米。(),【一题导练】,例：小明买东西付了50元钱，营业员将商品价格的小数点看错了一位，找给顾客45.75元，顾客说钱找多了，这件商品正确的标价是多少？,50-45.75=4.25（元）,4.2510=42.5（元）,答：这件商品正确的标价是42.5元。,【一题导练】,例：把一个数的小数点先向左移动两位，再向右移动三位，结果得0.6，那么原数是多少？,0.61001000=0.06,答：原数是6。,【一题导练】,例：甲数是乙数的100倍，若把乙数的小数点向左移动一位后是56.01，则甲数是多少？,56.0110100=56010,答：甲数是56010。,【一题导变】,例：一个数的小数点向左移动一位后比原数减少了46.8，原数是多少？,46.8（10-1）=46.89=5.25.210=52,答：原数是52。,【一题导变】,谢谢大家的聆听,