①3.8+4.29+4.2
②5.5×17.3+6.7×5.5
③2.33×0.5×4
④2.73×99
①10.9-0.9÷1.8
②82.6÷4÷0.25
③3.6÷0.4+1.25×5
④(3.2+0.16)÷0.8