①17.05-1.3-8.7+12.95
②0.32×2.5×12.5
③2.78×1.1-2.78
④16.1÷0.23-23.65
⑤5.04×3.7+3.7×3.96+3.7
⑥23.6÷[(6.8-5.4)×2.75-0.9]