97X32=(100一3)X32=100X32-3X32=3200-96=3104
利用乘法分配律算简便97x32=(100-3)x32=100x32-3x32=3200-96=3104
原式=(100-3)×32=3200-96=3200-100+4=3104
97×32=(100-3)×32=100×32-32×3=3200-96=3104