0.02x0.25x5X40 简便运算=（0.02x5）x（0.25x40）=0.1x10=1
0.02×0.25×5×40=(0.02×5)×(0.25×40)=0.1×10=1
答案如图
0.02x0.25x5x40=(0.02x5)x(0.25x40)=0.1x10=1
简便运算
