简便计算为0.4*63*2.5=0.4*2.5*63=1*63=63
0.4×63×2.5简便运算:0.4×63×2.5=(0.4×2.5)×63=1×63=63
0.4×63×2.5 =0.4×0.25×63 =0.1×63 =6.3
0.4×63×2.5=0.4×2.5×63=1×63=63乘法交换律。
