分析:(1)先算小括號里的加法,再算中括號里的乘法,最后算括號外的除法;
(2)先算小括號里的加法,再算中括號里的乘法,再算中括號里的減法,最后算括號外的減法;
(3)先算小括號里的減法,再算中括號里的乘法,最后算括號外的除法;
(4)先算小括號里的加法,再算括號外的乘法,最后算從左向右進行計算即可;
(5)先算乘法,再從左向右進行計算;
(6)先算除法算式,再算減法.
解答:解:(1)84.6÷[(54.8+39.2)×4.5]
=84.6÷[94×4.5]
=84.6÷423
=0.2
(2)[29.7-(5.4+1.65)×4]-0.6
=[29.7-7.05×4]-0.6
=[29.7-28.2]-0.6
=1.5-0.6
=0.9
(3)8÷[(40.75-9.5)×0.4]
=8÷[31.25×0.4]
=8÷12.5
=100
(4)11-46.8-4.5×(0.3+0.45)
=11-46.8-4.5×0.75
=11-46.8-3.375
=-35.8-3.375
=-39.175
(5)2.38+7.62+4.4×2.5
=2.38+7.62+11
=10+11
=21
(6)1÷0.01-19.84÷9.92
=100-2
=98
點評:完成本題要注意分析式中數(shù)據(jù),運用合適的簡便方法計算.