1*3*5+2*6*10+3*9*15=?(簡便運算)

1*3*5+2*6*10+3*9*15=?(簡便運算)


1*5*3+2*2*3*2*5+1*3*3*3*3*5
=1*3*5+8*3*5+27*3*5
=15*(1+8+27)
=15*36
=540