脱式计算（能简算的用简便算法）．（1）[9.2+0.8×（9-7.75）]÷0.4；（2）3.5×9.8+0.35×2；（3）28×2627；（4）[（23-35）×154+23]÷1112．

Question

脱式计算（能简算的用简便算法）．
（1）[9.2+0.8×（9-7.75）]÷0.4；     
（2）3.5×9.8+0.35×2；
（3）28×(26)/(27)；                    
（4）[（(2)/(3)-(3)/(5)）×(15)/(4)+(2)/(3)]÷(11)/(12)．

Answer 1

（1）[9.2+0.8×（9-7.75）]÷0.4
=[9.2+0.8×1.25]÷4
=[9.2+1]÷4
=2.55         
 
（2）3.5×9.8+0.35×2
=3.5×（9.8+0.2）
=3.5×10
=35

（3）28×(26)/(27)
=（27+1）×(26)/(27)
=27×(26)/(27)+(26)/(27)
=26+(26)/(27)
=26(26)/(27)

（4）[（(2)/(3)-(3)/(5)）×(15)/(4)+(2)/(3)]÷(11)/(12)
=[(1)/(15)×(15)/(4)+(2)/(3)]÷(11)/(12)
=[(1)/(4)+(2)/(3)]÷(11)/(12)
=(11)/(12)×(12)/(11)
=1