用递等式计算.1.15/4*12/5-12/5/120% =9-2 =7 2.100.1-（2.625+0.425）*30 =100.1-3.05*30 =100.1-91.5 =8.6 3.99/{23/4-（9/5+21/5*2/7）} =99/[23/4-3] =99/11/4] =36 4.（1/4+3/8）/（1-3/10） =5/8/(7/10) =25/2... 用递等式计算.1.15/4*12/5-12/5/120% =9-2 =7 2.100.1-（2.625+0.425）*30 =100.1-3.05*30 =100.1-91.5 =8.6 3.99/{23/4-（9/5+21/5*2/7）} =99/[23/4-3] =99/11/4] =36 4.（1/4+3/8）/（1-3/10） =5/8/(7/10) =25/2...