7.2×14.5＋17×2.8怎样简便计算？并且说明一下，那些插入来的数全部都说明一下。

---

（7.2+2.8）x14.5+(17-14.5)x2.8
=10x14.5+2.5x4x0.7
=145+7
=152

---

=14.5*7.2+(14.5+2.5)*2.8
=14.5*(7.2+2.8)+2.5*2.8
=145+2.5*2+2.5*0.8
=145+5+2
=152

---