《2021年五年級數(shù)學(xué)上冊二小數(shù)乘法第5課時積的近似值習(xí)題課件冀教版》由會員分享,可在線閱讀,更多相關(guān)《2021年五年級數(shù)學(xué)上冊二小數(shù)乘法第5課時積的近似值習(xí)題課件冀教版(11頁珍藏版)》請?jiān)谘b配圖網(wǎng)上搜索。
1、第,5,課時 積的近似值,2,小數(shù)乘法,JJ,,五年級上冊,1,2,3,4,5,6,7,提示,:,點(diǎn)擊 進(jìn)入習(xí)題,,知識點(diǎn),,用“四舍五入法”求積的近似值,1,.填一填。,,(1),求積的近似值時,保留一位小數(shù)表示省略,(,,),位后面的尾數(shù),要把,(,,),位上的數(shù)進(jìn)行“四舍五入”。,,(2)0.35×0.7,的積是,(,,),,保留一位小數(shù)約是,(,,),;,0.27×2.18,的積是,(,,),,保留兩位小數(shù)約是,(,,),。,十分,百分,0.245,0.2,0.5886,0.59,(,已知一個三位小數(shù)“四舍五入”后約是,7.80,,這個三位小數(shù)最大是,(,,),,最小是,(
2、,,),。,7.804,,7.795,2,.按要求填表。,0.5338,,1,,0.5,,0.53,1.692,,2,,1.7,,1.69,26.852,,27,,26.9,,26.85,,3.,列豎式計(jì)算。,,(1),得數(shù)保留整數(shù)。,,6.14×2.6,≈,,0.36×7.5≈,,16,3,(2),得數(shù)保留一位小數(shù)。,,3.15×0.5≈ 6.106×5.14≈,1.6,31.4,,易錯辨析,辨析:積的近似值末尾的,0,不能去掉,4,.下面的近似值對嗎?若不對,請改正。,,(1)0.42×2.38,的積保留兩位小數(shù)約是,1,。,,,(2)0.95×0.95,的積保留兩位小數(shù)約是,0.9,。,不對,1.00,不對,0.90,,提升點(diǎn),1,人民幣兌換,5,.某日,,1,歐元可以兌換人民幣,7.83,元,媽媽有,7.5,歐元,到銀行可以兌換人民幣多少元?,(,得數(shù)保留一位小數(shù),),5.7.83×7.5≈58.7(,元,),,提升點(diǎn),2,用積的近似值靈活地解決問題,6,.包裝,11,個這樣的禮盒,需要準(zhǔn)備多長的彩帶?,(,得數(shù)保留整數(shù),),0.85×11,=,9.35≈10(,米,),,7,.做一套校服要用布,2.25,米,如果為,45,名同學(xué)各做一套這樣的校服,那么至少應(yīng)準(zhǔn)備多少米布?,(,得數(shù)保留整數(shù),),7.2.25×45≈102(,米,),