怎样算简便就怎样算．
①2.43×99+2.43                     
②6.8+1.25×6.8×8
③（8.14﹣3.75）÷2.5÷4                 
④4.58+2.39+（5.42+7.61）
⑤6.3÷2.8                          
⑥26.7﹣0.5×0.5﹣0.75．