0.9+（0.9-0.9）*0.9-0.9=0.9+0-0.9 = 02.37-1.75+1.63-2.25= 2.37+1.63-2.25-1.75= 4 - 4 = 00.125*0.25*0.5*64= 0.5^3 * 0.5^2 * 0.5 * 2^6= 0.5^(3+2+1) * 2^6= (0.5 * 2)^6 = 1^是什么意思