2.6×0.39+2.7×0.38+2.8×0.37求和的简便算法

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2.6×0.39+2.7×0.38+2.8×0.37求和的简便算法

2.6×0.39+2.7×0.38+2.8×0.37求和的简便算法
2.6×0.39+2.7×0.38+2.8×0.37求和的简便算法

2.6×0.39+2.7×0.38+2.8×0.37求和的简便算法
(2.7-0.1)×(0.38+0.01)+2.7×0.38+(2.7+0.1)×(0.38-0.01)
=2.7×0.38×3-2×0.1×0.01
=3.076

2.6×0.39+2.7×0.38+2.8×0.37
=2.6*0.38+2.7*0.38+2.8*0.38
=(2.6+2.7+2.8)*0.38
=8.1*0.38
=3.078

2.6×0.39+2.7×0.38+2.8×0.37
=2.6×(4-0.01)+2.7×(4-0.02)+2.8×(4-0.03)
=10.4-0.026+10.8-0.054+11.2-0.084
=32.4-0.164
=32.236

2.6×0.39+2.7×0.38+2.8×0.37
=2.6×0.38+2.7×0.38+2.8×0.38+2.6-2.8
=0.38×2.7×3-0.2
=1.738

(2.7-0.1)×(0.38+0.01)+2.7×0.38+(2.7+0.1)×(0.38-0.01)
=2.7×0.38×3-2×0.1×0.01
=3.076

再简便也不如计算器快。