【2020新】北師大版四年級數(shù)學下冊《15街心廣場》課件

1、 街心廣場 （建議一課時完成）第三單元 小數(shù)乘法 四年級下冊 課后作業(yè)探索新知積的小數(shù)位數(shù)與乘數(shù)的小數(shù)位數(shù)的關系1課堂探究點2課時流程課堂小結當堂檢測北師大版四年級數(shù)學下冊20米30米北師大版四年級數(shù)學下冊探究點 積的小數(shù)位數(shù)與乘數(shù)的小數(shù)位數(shù)的關系先說一說街心廣場上的數(shù)學信息，再算一算，填一填。街心廣場花壇地磚面積/平方米北師大版四年級數(shù)學下冊淘氣在計算地磚的面積時遇到了困難，你能幫幫他嗎？0.30.2 （ ）0.3米3分米0.2米2分米326（平方分米）6平方分米0.06（平方米）6（平方米）0.3米0.2米321米1米0.01平方米6個0.01是0.06平方米。0.06

2、平方米北師大版四年級數(shù)學下冊結合上面的計算過程，想一想乘數(shù)和積之間有什么關系。30 206003 2 6北師大版四年級數(shù)學下冊積的小數(shù)位數(shù)與乘數(shù)的小數(shù)位數(shù)有什么關系？算一算，想一想。0.10.30.1320.130.2第一個乘數(shù)的小數(shù)位數(shù)第二個乘數(shù)的小數(shù)位數(shù)積的小數(shù)位數(shù)0.260.026011112202213北師大版四年級數(shù)學下冊小試牛刀（源于典中點）1算一算。(1)10101000. 1 8北師大版四年級數(shù)學下冊(2)北師大版四年級數(shù)學下冊2填一填。(1)一個乘數(shù)擴大到原來的10倍，另一個乘數(shù)擴大到原來的100倍，積就擴大到原來的( )倍。(2)一

3、個乘數(shù)縮小到原來的 ，另一個乘數(shù)也縮小到原來的 ，積就縮小到原來的()。1000北師大版四年級數(shù)學下冊3把表格補充完整，你發(fā)現(xiàn)了什么？我發(fā)現(xiàn)：_。算式第一個乘數(shù)的小數(shù)位數(shù)第二個乘數(shù)的小數(shù)位數(shù)積的小數(shù)位數(shù)0.0330.090.20.28202001112兩個乘數(shù)一共有幾位小數(shù)，積就有幾位小數(shù)(答案不唯一)北師大版四年級數(shù)學下冊4根據(jù)第一欄的積快速寫出后面每欄的積。乘數(shù)12121.21.2121201.2乘數(shù)1515050.15積1801800181.818180.18北師大版四年級數(shù)學下冊歸納總結：（講解源于典中點）兩個數(shù)相乘，每一個乘數(shù)都乘(或除以)一

4、個不為0的數(shù)，它們的積就乘(或除以)這兩個不為0的數(shù)的乘積。北師大版四年級數(shù)學下冊小試牛刀（教材P39練一練）你會計算這塊拼圖的面積嗎？想一想，算一算。 （1）與同伴交流你的想法。 （2）結合計算過程說一說，積的 小數(shù)位數(shù)與乘數(shù)的小數(shù)位數(shù) 有什么關系？略。9(平方米)積的小數(shù)位數(shù)是乘數(shù)的小數(shù)位數(shù)之和。北師大版四年級數(shù)學下冊根據(jù)第一欄的積很快寫出后面每欄的積。乘數(shù)363.6363.60.36乘數(shù)242.42.4242.4積8648.6486.486.40.864北師大版四年級數(shù)學下冊淘氣的計算器上的小數(shù)點無法顯示了，你能幫他得到正確答案嗎？北師大版四年級數(shù)學下冊明明每天上學和放

5、學都要乘坐一次公交車，每乘一次公交車花0.2元。明明的公交卡里還剩3元，夠他一周5天上學和放學用嗎？0.220.4（元）0.452（元）夠他一周5天上學和放學用。根據(jù)1312156，在 里填上適當?shù)臄?shù)。13 1.2 1.3 1.21.312 13 2 1.31200.13 1.2 130 1.2點撥：答案不唯一。易錯辨析5判斷。(對的畫“”，錯的畫“”)(1)2.45的積的小數(shù)位數(shù)有0位。()(2)0.1258的積有三位小數(shù)。()辨析：兩個乘數(shù)一個共有幾位小數(shù)，積就有幾位小數(shù)。版權申明本文部分內容，包括文字、圖片、以及設計等在網上搜集整理.版權為個人所有This artic

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28、obligee. 轉載或引用本文內容必須是以新聞性或資料性公共免費信息為使用目地地合理、善意引用，不得對本文內容原意進行曲解、修改，并自負版權等法律責任.Reproduction or quotation of the content of this article must be reasonable and good-faith citation for the use of news or informative public free information. It shall not misinterpret or modify the original intention of the content of this article, and shall bear legal liability such as copyright.版權申明本文部分內容，包括文字、圖片、以及設計等在網上搜集整理.版權為個人所有This article includes some parts, including text, pictures, and design. Copyright is personal ownership.用戶可將本文地內容或服務用于個人學習、研究或欣賞，以及其他非商業(yè)性或非盈利性用途，但同時應遵守著作權法及其他相關法律地規(guī)定，不得侵