10/0.2/2.5 用简便计算 1.25*3.2*0.8 14.64+3.7*2.8 64*4.5+3.6*45 14

10/0.2/2.5 = 10 / (0.2*2.5) = 10 / 0.5 = 20;
1.25*3.2*0.8 = 1.25 * 0.8 * 3.2 = 1 * 3.2 = 3.2
14.64+3.7*2.8 = 14.64 + 3.7 * (3-0.2) = 14.64 + 11.1 - 0.74 = 25.74 -0.74 = 25
64*4.5+3.6*45 = 64*4.5+36*4.5 = (64+36)*4.5 = 100*4.5 = 450
14.5*102 = 14.5*(100+2) = 14.5*100 + 14.5*2 = 1450 + 29 = 1479
8.4/0.21/0.5 = 0.4*3*7 / (0.03*7)/0.5 = 0.4/(0.01*0.5) = 80