1.2×12.3=14.76
1.2X12.3=1.2X1.2X10+1.2X0.3=14.4+0.36=14.76
1.2x12.3=12.3x(1+0.2)(乘法分配律)=12.3x1+12.3x0.2=12.3+2.46=14.76