小數(shù)點(diǎn)向左移動(dòng)引起小數(shù)大小變化的規(guī)律

1、探索小數(shù)點(diǎn)向左移動(dòng)的規(guī)律,21.5除以10、100、1000各是多少？,21.5÷10＝2.15,21.5÷100＝0.215,21.5÷1000＝0.0215,21.5÷10＝2.15,21.5÷100＝0.215,21.5÷1000＝0.0215,,21.5除以10，得2.15，小數(shù)點(diǎn)向左移動(dòng)了一位。,21.5÷10＝2.15,21.5÷100＝0.21

2、5,21.5÷1000＝0.0215,,21.5除以100，得0.215，小數(shù)點(diǎn)向左移動(dòng)了兩位。,21.5÷10＝2.15,21.5÷100＝0.215,21.5÷1000＝0.0215,,21.5除以1000，得0.0215，小數(shù)點(diǎn)向左移動(dòng)了三位。,一個(gè)小數(shù)除以10、100、1000……,只要把這個(gè)小數(shù)的小數(shù)點(diǎn)向左移動(dòng)一位、兩位、三位……,填寫下表。,,152.7,32.1,0.8,600,&

3、#247;10,÷100,÷1000,1.527,15.27,0.1527,0.321,3.21,0.0321,0.008,0.08,0.0008,6,60,0.6,32.1,÷1000,0.0321,在括號(hào)里填上合適的數(shù)，再在小組里說說你是怎樣想的。,54.2÷( )＝5.42,2.17÷( )＝0.0217,3.48÷( )＝0.

4、348,102.2÷( )＝0.1022,10÷( )＝0.1,540÷( )＝0.54,10,1000,100,100,10,1000,學(xué)校體育室購買了幾種體育用品，數(shù)量和總價(jià)如下表。計(jì)算出每種體育用品的單價(jià)，并填入表中。,單 價(jià),數(shù) 量,總 價(jià),100根,10個(gè),100個(gè),100個(gè),85元,432元,70元,150元,0.85元,43.2元,0.7元,1.5元,

5、直接寫出得數(shù)。,56.3÷10 =,0.03÷10 =,16.5÷100 =,8.4÷100 =,40÷1000 =,28.9÷1000 =,5.63,0.003,0.165,0.084,0.04,0.0289,下表是幾種動(dòng)物的體重。,長頸鹿的體重是多少噸？,500千克＝( )噸,,,用計(jì)算器計(jì)算。,500÷1000＝0.5(噸),直接把500的小數(shù)點(diǎn)向左移

6、動(dòng)三位。,500千克＝0.5噸,大猩猩和企鵝的體重各是多少噸？,225千克＝( )噸,40千克＝( )噸,0.225,0.04,想：225÷1000=0.225,想：40÷1000=0.04,35厘米＝( )米,0.35,79千克＝( )噸,420米＝( )千米,43分米＝( )米,3850克＝( )千克,600毫升

7、＝( )升,0.079,4.3,0.42,0.6,3.85,照這樣計(jì)算，1000噸這種鐵礦石可以煉鐵多少噸？,6.05÷10×1000＝0.605×1000 ＝605(噸),答：1000噸這種鐵礦石可以煉鐵605噸。,6.05×(1000÷10)＝6.05× 100＝605 (噸),一個(gè)小數(shù)除以10、100、1000 ……只要把這個(gè)小數(shù)的小數(shù)點(diǎn)分別向左