Question

20．在計(jì)算小數(shù)乘法時(shí)，也像計(jì)算小數(shù)加法一樣，把小數(shù)點(diǎn)對(duì)齊再計(jì)算．×．（判斷對(duì)錯(cuò)）

Answer 1

分析 計(jì)算小數(shù)乘法，是按照整數(shù)乘法算出積，再看因數(shù)中一共有幾位小數(shù)，就從積的右邊起，向左數(shù)出幾位，點(diǎn)上小數(shù)點(diǎn)，因此小數(shù)乘法不需要小數(shù)點(diǎn)對(duì)齊，據(jù)此判斷即可．

解答 解：列豎式計(jì)算小數(shù)乘法時(shí)，應(yīng)把因數(shù)的末尾對(duì)齊，而不是把因數(shù)中的小數(shù)點(diǎn)對(duì)齊．
故在計(jì)算小數(shù)乘法時(shí)，也像計(jì)算小數(shù)加法一樣，把小數(shù)點(diǎn)對(duì)齊再計(jì)算的說法是錯(cuò)誤的．
故答案為：×．

點(diǎn)評(píng) 此題考查學(xué)生列豎式計(jì)算小數(shù)乘法的方法，一般把因數(shù)末尾對(duì)齊，不需要把因數(shù)中的小數(shù)點(diǎn)對(duì)齊．