1/6 + 1/2 -1/6 =1/2, 7.5-(2.5+3.8)=1.2, 4/5 - 7/10 =1/10, 2 - 1/6 -1/3 =1.5 0.51÷17＝0.03, 32.8＋19＝51.8, 5.2÷1.3＝4, 1.6×0....要全部都有简便！！！对不起，没了