计算下面各题，怎样简便就怎样算．
1.29+3.7+0.71+6.3             23.4﹣8.54﹣1.46           6.75×0.5+4.86
19×3.6﹣3.6×9               2.5×1.8×0.04             10.24÷1.25÷8．