原式=40x25x125+2x(4x25x125)=1000x125+2x(100x125)=125000+25000=150000
(40+8)x125x25=40×25x125+8x125x25=1000x125+1000x25=150000
=40*125*25+8*125*25=1000*125+1000*25=1000*150=150000
分成40*25*125+8*125*25