小學(xué)數(shù)學(xué)北師大2011課標(biāo)版四年級小數(shù)點(diǎn)搬家教學(xué)課件 (2).ppt

小數(shù)點(diǎn)搬家,北師大版四年級下冊第三單元,螞蟻快餐廳,0.01元,情境導(dǎo)入,這么多客人！,螞蟻快餐廳,0.10元,情境導(dǎo)入,漲價(jià)了！,螞蟻快餐廳,1.00元,情境導(dǎo)入,小數(shù)點(diǎn)在向右搬家。,太貴了！,新知探究,小數(shù)點(diǎn)向右移動(dòng)，小數(shù)的大小發(fā)生了變化？想一想，說一說。,小數(shù)點(diǎn)向右移一位,0.10元=1角,小數(shù)點(diǎn)向右移兩位,1.00元=1元,0.01元=1分,新知探究,小數(shù)點(diǎn)向右移動(dòng)，小數(shù)的大小發(fā)生了變化？想一想，說一說。,百分位,十分位,個(gè)位,十位,0,.,0,1,0,.,1,0,1,.,0,0,小數(shù)點(diǎn)向右搬家，快餐價(jià)格將發(fā)生怎么樣的變化？小數(shù)點(diǎn)向右移動(dòng)一位，這個(gè)數(shù)將擴(kuò)大到原來的倍；小數(shù)點(diǎn)向右移動(dòng)兩位，這個(gè)數(shù)將擴(kuò)大到原來的倍；小數(shù)點(diǎn)向右移動(dòng)三位，這個(gè)數(shù)將擴(kuò)大到原來的倍。,新知探究,10,100,1000,新知探究,小數(shù)點(diǎn)向左移動(dòng)，小數(shù)的大小發(fā)生了什么變化？說一說，填一填。,1,0.1,0.01,新知探究,小數(shù)點(diǎn)向左搬家，快餐價(jià)格將發(fā)生怎么樣的變化？小數(shù)點(diǎn)向左移動(dòng)一位，這個(gè)數(shù)將縮小到原數(shù)的；小數(shù)點(diǎn)向左移動(dòng)兩位，這個(gè)數(shù)將縮小到原數(shù)的；小數(shù)點(diǎn)向左移動(dòng)三位，這個(gè)數(shù)將縮小到原數(shù)的。,新知探究,請你再舉個(gè)例子說說“小數(shù)點(diǎn)移動(dòng)后小數(shù)的大小發(fā)生了什么變化”。,說一說，試一試！,新知探究,看圖想一想，說一說。,0.01,0.1,1,0.01的10倍、100倍各是多少？,新知探究,0.01的10倍、100倍各是多少？,0.0110=0.1,0.01100=1,新知探究,看圖想一想，說一說。,新知探究,110=0.1,1100=0.01,鞏固練習(xí),1.填一填。,（1）,2,0.2,0.02,0.2是2的（）,0.02是2的（）,鞏固練習(xí),1.填一填。,（2）,0.05元,0.5元,5元,0.5元是0.05元的（）,5元是0.05元的