脱式计算
3.94+34.3×0.2                2.08×（9.6÷2.4）÷4.8．

递等式计算      
1.08÷（3.94+34.3×0.2）-0.08             3.27×（80.5-9.84÷0.16）
（4.25-4.25×0.8）÷（1.3+0.4）125÷[（17.2-4.5×3.6）÷0.32]．

①6.81+6.81×99                       
②0.25×185×40
③3.94+34.3×0.2                      
④3.6÷0.4-1.5×3
⑤2.08×（9.6÷2.4）÷4.8             
⑥68.1-77.7÷0.7×0.5．