Question

13．用豎式計(jì)算，得數(shù)保留兩位小數(shù)（2除外） 
8.796×0.25               
10.5÷0.75               
7÷19．

Answer 1

分析 （1）題根據(jù)小數(shù)乘法的計(jì)算方法計(jì)算；先按照整數(shù)乘法法則算出積，再看因數(shù)中一共有幾位小數(shù)，就從積的右邊向左數(shù)出幾位，點(diǎn)上小數(shù)點(diǎn)；
（2）題根據(jù)小數(shù)除法的計(jì)算法則進(jìn)行計(jì)算：先移動(dòng)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(dòng)了幾位，被除數(shù)的小數(shù)點(diǎn)也向右移動(dòng)幾位（位數(shù)不夠的，在被除數(shù)的末尾用“0”補(bǔ)足）；然后按照除數(shù)是整數(shù)的小數(shù)除法進(jìn)行計(jì)算；
（3）題根據(jù)除數(shù)是兩位數(shù)的除法的計(jì)算法則進(jìn)行計(jì)算：除數(shù)是兩位數(shù)的除法先看被除數(shù)的前兩位，不夠除時(shí)再看前三位．被除數(shù)只有一位時(shí)添0補(bǔ)足位數(shù)，進(jìn)行計(jì)算．

解答 解：8.796×0.25≈2.20，


10.5÷0.75=14


7÷19≈0.37

點(diǎn)評 此題主要考查小數(shù)乘法、小數(shù)除法和整數(shù)除法的計(jì)算方法，關(guān)鍵要注意小數(shù)點(diǎn)的位置．