455+130+170+245
47×28+47×72
125×32×25
97×101
36×201﹣36
(80+4)×125
①250-250÷25×2
②18÷ ×
③5.2÷0.4÷2.5
④(34- )÷17
⑤4.3×1.75-1.75+ ×6.7
⑥ ×[(72.8-69.6)÷ ]