计算结果是3.04
计算的详细步骤看图。
(1.2x0.4+1.2x0.8+0.4x0.8)×2-1.2x0.4
=(0.48+0.96+0.32)x2-0.48
=3.52-0.48
=3.04
(1.2×0.4+1.2×0.8+0.4×0.8)×2-1.2×0.4
=1.2×0.4×2+1.2×0.8×2+0.4×0.8×2-1.2×0.4
=1.2×0.8+1.2×1.6+0.8×0.8-1.2×0.4
=1.2×(0.8+1.6-0.4)+0.8×0.8
=1.2×2+0.64
=2.4+0.64
=3.04
这道题运用了乘法结合律、交换率、分配率。
见图