Question

計(jì)算下面各題． 234÷7.2+6.5×0.8	4.8+1.52÷0.4-0.4×6
（4.5-2.7）×（3.8+0.75）	7.2÷[（7.22-6.41）÷9]．

Answer 1

解：①234÷7.2+6.5×0.8，
=32.5+5.2，
=37.7；

②4.8+1.52÷0.4-0.4×6，
=4.8+3.8-2.4，
=6.2；

③（4.5-2.7）×（3.8+0.75），
=1.8×4.55，
=8.19；

④7.2÷[（7.22-6.41）÷9]，
=7.2÷[0.81÷9]，
=7.2÷0.09，
=80．
分析：①②④運(yùn)用小數(shù)除法的計(jì)算法則及小數(shù)乘法的計(jì)算法則進(jìn)行計(jì)算，計(jì)算小數(shù)除法時商的小數(shù)點(diǎn)與被除數(shù)的小數(shù)點(diǎn)對齊，小數(shù)的乘法積的小數(shù)位數(shù)是兩個因數(shù)小數(shù)位數(shù)的和．
③運(yùn)用小數(shù)加減法的法則進(jìn)行計(jì)算，小數(shù)點(diǎn)要對齊．
點(diǎn)評：小數(shù)除法計(jì)算，注意商的小數(shù)點(diǎn)與被除數(shù)的小數(shù)點(diǎn)對齊．