(12*21*45*10.2)/(15*0.7*51)
=(3*4*3*7*5*9*10.2)/(3*5*7*0.1*3*17)
= (4*9*10.2)/(0.1*17)
=(4*9*17*6*0.1)/(0.1*17)
=4*9*6
=216