用递等式计算，能简算的要简算．
1÷﹙18.5﹣4.5×3﹚
÷
﹣
×
×
×40．
计算下面各题（能简算的要简算）．
①4×0.8×2.5×12.5 ②
÷[1﹣（
+
）]③（2.8+3.85÷3.5）×4.6
④6.5×1.83+0.17×6.5⑤（
+
）×8+
⑥
÷[
×（0.4+
）]．
0.89×0.48+0.89×0.520.25×13.7×0.44.2×101
3.6×992.5×32×1.250.125×88
56.5×99+56.5（1.25﹣0.125）×845÷0.09÷0.5
17.8÷（1.78×4）
计算下列各题．（能简算的要简算）．
91÷2.6÷0.05=6.3×3.7+6.3×6.3=（3.7+1.7×0.4）÷2.5=
7.28+3.2÷2.5=0.74+0.9×7.4=7.8÷0.125÷0.8=
计算下面各题，能用简便算法的用简便算法
3.045+2.7×6.9=18.94﹣2.5×4=
3.65×2.8+3.65×7.2=13.54×102﹣2×13.54=