5.26+7+1.74 27.85-(7.85+3.9)
5.6+2.7-3.6 10-2.75-3.25
15.25-3.1+0.65-4.9
①3.6﹣2.8+7.4﹣7.2
②1.25×1.6×25
③÷4
④÷[(﹣)×]