计算下面各题，能简算的要简算．
8.5×〔（2.36+2.42）÷0.25〕           3.9÷（1.3+0.6）×6           205×99
4.25×6.3+3.7×4.25                  25.6﹣7.49﹣2.51             〔2.5﹣（6.8﹣4.9）〕×0.8．