Question

判斷積的小數(shù)位數(shù)．
4.56×9

 

；     0.057×0.06

 

；     0.9×0.124

 

．

Answer 1

考點：小數(shù)乘法

專題：運算順序及法則

分析：先分別找到兩個因數(shù)中一共的小數(shù)位數(shù)，再看得數(shù)的小數(shù)部分末尾是否有0進行分析求解．

解答： 解：4.56×9 積的小數(shù)位數(shù)是2；     
0.057×0.06 積的小數(shù)位數(shù)是5；     
0.9×0.124 積的小數(shù)位數(shù)是4．
故答案為：積的小數(shù)位數(shù)是2；積的小數(shù)位數(shù)是5；積的小數(shù)位數(shù)是4．

點評：小數(shù)乘法法則：按整數(shù)乘法的法則算出積； 再看因數(shù)中一共有幾位小數(shù)，就從得數(shù)的右邊起數(shù)出幾位，點上小數(shù)點，得數(shù)的小數(shù)部分末尾有0，一般要把0去掉．