(1*3*5+2*6*10+3*9*15+4*12*20)/(1*2*3+2*4*6+3*6*9+4*8*12) jiansuan

(1*3*5+2*6*10+3*9*15+4*12*20)/(1*2*3+2*4*6+3*6*9+4*8*12) jiansuan

Molecule = 1 * 3 * 5 + 2 * 1 * 2 * 3 * 2 * 5 + 3 * 1 * 3 * 3 * 3 * 5 + 4 * 1 * 4 * 3 * 4 * 5 = 1 * 3 * 5 + 2 & sup3; * 1 * 3 * 5 + 3 & sup3; * 1 * 3 * 5 + 4 & sup3; * 1 * 3 * 5 = (1 + 2 & sup3; + 3 & sup3; + 4 & sup3;) * 1 * 3 * 5 denominator = 1 * 2 * 3 + (2 * 2) * 1 * 2 * 3 + (3 * 3) * 1 * 2 * 3 + (4 * 4) * 1 * 2 * 3 = (1 + 2 & sup3; + 3 & sup3; +