1.在計(jì)算被減數(shù)的小數(shù)位數(shù)比減數(shù)的小數(shù)位數(shù)少時(shí),學(xué)生常常會受整數(shù)減法的影響,將末尾的數(shù)對齊。因此,通過舉例子,引導(dǎo)學(xué)生討論,使學(xué)生發(fā)現(xiàn):“凡是遇到被減數(shù)的小數(shù)位數(shù)比減數(shù)的小數(shù)位數(shù)少時(shí),可以先在被減數(shù)的末尾補(bǔ)0,使被減數(shù)的小數(shù)位數(shù)與減數(shù)的小數(shù)位數(shù)一樣多,再按照整數(shù)減法的計(jì)算方法進(jìn)行計(jì)算?！睂W(xué)生按照這樣的方法列豎式后,正確率明顯提高。2.在口算整數(shù)加小數(shù)時(shí),學(xué)生會將這個(gè)整數(shù)與小數(shù)的末尾對齊后相加。如8+1.2=2,0.46+4=0.5等。究其原因,是學(xué)生在口算時(shí)不仔細(xì)看題,當(dāng)作整數(shù)加法進(jìn)行口算,要速度,不要質(zhì)量。對此,就要加強(qiáng)口算訓(xùn)練,日積月累,長期訓(xùn)練,逐步提高正確率