1. (2020五上·新会期中) 下列各题，怎样算简便就怎样算

①25.63＋3.7×2.8

②9.2+9.728÷3.2×1.5

③8.6×10.1

④8.4÷0.2÷0.5

⑤9.9+9.9×99

⑥5.78 ×2.57＋2.57×3.22＋2.57