2﹣÷﹣ 8.1÷(5﹣0.005×700×1)〔1.8﹣1.8×(1.8﹣1.8)〕÷0.36 〔5﹣1.7÷(2﹣1)〕×1 51÷+71÷+91÷6÷〔35×(+)〕×4.8 1+3+5+7+9.