49.5÷9+35.1÷7.8 =5.5+4.5=10[2.5-8分之31÷{6分之11+0.75]}×17分之30 =（2.5-31/8*12/31）*30/17=（2.5-1.5）*30/17=1*30/17=30/1719.63×99+19.63=19.63*（99+1）=19.63*100=1963{7.6-10.5×0.6}×13分之10=（7...