先把25x36分解成5x5x6x6=5x6x5x6=900然后就直接35x900=31500
35=30+525=20+536=30+6则35×(25×36)=(30+5)((20+5)(30+6))=(30+5)(20*30+20*6+5*30+5*6)=(30+5)(600+120+150+30)=(30+5)*900=30*900+5*900=27000+4500=31500
35*25*36=35*(25*4)*9=35*9*100=315*100=31500