人教五年級上冊數(shù)學(xué)《一個數(shù)除以小數(shù)(被除數(shù)的小數(shù)位數(shù)比除數(shù)少)》教學(xué)課件

第5課時一個數(shù)除以小數(shù)(被除數(shù)的小數(shù)位數(shù)比除數(shù)少)人教版數(shù)學(xué)五年級上冊課件3小數(shù)除法被除數(shù)273273027.30.273除數(shù)131.30.130.013商212121你能根據(jù)第一列里的數(shù)，填出其他各列里的數(shù)嗎？1302.732121探究點(diǎn)

被除數(shù)的位數(shù)比除數(shù)少的除法被除數(shù)小數(shù)位數(shù)不夠怎么辦？3.78÷2.8＝÷28把下面的算式轉(zhuǎn)化成除數(shù)是整數(shù)的除法算式。12.6÷0.28＝÷2837.8？12.6÷0.28＝思考并回答：1.除數(shù)是幾位小數(shù)？被除數(shù)是幾位小數(shù)？2.要把除數(shù)變成整數(shù)，應(yīng)該怎么辦？12.6÷0.28＝04112

140014512.60.28045在被除數(shù)的末尾用“0”補(bǔ)足。被除數(shù)位數(shù)不夠怎么辦呢？0

12.6÷0.28＝4112140014512.60.2804597.65÷0.85＝7.650.8597650這兩道題有什么區(qū)別呢？右邊這道題被除數(shù)的末尾位數(shù)不夠，需要用“0”補(bǔ)足。大家來討論：除數(shù)是小數(shù)的除法應(yīng)該怎樣計(jì)算？先移動除數(shù)的小數(shù)點(diǎn)，使它變成整數(shù)。除數(shù)的小數(shù)點(diǎn)向右移動幾位，被除數(shù)的小數(shù)點(diǎn)也向右移動幾位。位數(shù)不夠的，在被除數(shù)的末尾用0補(bǔ)足。然后按除數(shù)是整數(shù)的小數(shù)除法進(jìn)行計(jì)算。算一算25.6÷0.032＝80008256

025.60.032000要使除數(shù)0.032轉(zhuǎn)化成整數(shù)，小數(shù)點(diǎn)要向右移動幾位？1．下面的做法中，錯誤的是(

)。A．7.2÷0.18＝720÷18B．13÷0.65＝1300÷65C．25.6÷0.032＝2560÷32D．7.5÷0.15＝750÷15C2．列豎式計(jì)算。50.4÷0.28＝48.6÷0.27＝1801801.在里填上“＞”“＜”或“＝”。8.9÷1.58.9

1.36÷0.981.362.16÷12.16

7.85÷1.27.85×1.2<

>＝<點(diǎn)撥：在被除數(shù)大于0的情況下，若除數(shù)大于1，商小于被除數(shù)；若除數(shù)等于1，商等于被除數(shù)；若除數(shù)大于0且小于1，商大于被除數(shù)。34.8÷1.634.834.8÷0.1634.834.8÷134.82.在○里填上“＞”“＜”“=”。＞＜=你發(fā)現(xiàn)規(guī)律了嗎？當(dāng)除數(shù)＞1時，被除數(shù)＞商；當(dāng)除數(shù)＜1時，被除數(shù)＜商；當(dāng)除數(shù)=1時，被除數(shù)=商。除數(shù)是小數(shù)的除法的計(jì)算方法：(1)先移動除數(shù)的小數(shù)點(diǎn)，使它變成整數(shù);(2)除數(shù)的小數(shù)點(diǎn)