不對(duì).
比如,0.2*0.5=0.1.這里兩個(gè)因數(shù)的小數(shù)之和是2,積的小數(shù)是1
再如,0.02*0.05=0.001.這里兩個(gè)因數(shù)的小數(shù)之和是4,積的小數(shù)是3
上面兩個(gè)算式中,為什么積的小數(shù)會(huì)比兩個(gè)因數(shù)的小數(shù)之和少一個(gè)呢?
其實(shí),0.2*0.5的算法是,先用2*5,再將小數(shù)點(diǎn)移兩位,即10的小數(shù)點(diǎn)移兩位,=0.10.而在小數(shù)乘法里,小數(shù)最后的零通常省略.所以0.2*0.5的小數(shù)是1,不是2
同樣地,當(dāng)兩個(gè)因數(shù)的小數(shù)之和是4時(shí),積的最后可能也是0,也被省略.
如,0.04*0.25=0.0100=0.01,積的小數(shù)是2
如,0.8*0.123=0.1000=0.1,積的小數(shù)是1
由此可見(jiàn),在小數(shù)乘法里,兩個(gè)因數(shù)的小數(shù)之和是4,那積的小數(shù)最大是4