﹙12.5－2.5﹚÷2.5×0.5+1＝10÷2.5×0.5+1＝4×0.5+1＝2+1＝3 ﹙12.5－2.5﹚÷2.5×0.5+1＝10÷2.5×0.5+1＝4×0.5+1＝2+1＝3