简便计算 急！
2个回答
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1/2+1/2×1/4+1/2×3/4×1/6+1/2×3/4×5/6×1/8+1/2×3/4×5/6×7/8
=1/2+1/2×1/4+1/2×3/4×1/6+(1/2×3/4×5/6×1/8+1/2×3/4×5/6×7/8)
=1/2+1/2×1/4+1/2×3/4×1/6+[1/2×3/4×5/6×(1/8+7/8)]
=1/2+1/2×1/4+1/2×3/4×1/6+1/2×3/4×5/6×1
=1/2+1/2×1/4+1/2×3/4×1/6+1/2×3/4×5/6
=1/2+1/2×1/4+(1/2×3/4×1/6+1/2×3/4×5/6)
=1/2+1/2×1/4+[1/2×3/4×(1/6+5/6)]
=1/2+1/2×1/4+1/2×3/4×1
=1/2+(1/2×1/4+1/2×3/4)
=1/2+1/2×(1/4+3/4)
=1/2+1/2×1
=1/2+1/2
=1
=1/2+1/2×1/4+1/2×3/4×1/6+(1/2×3/4×5/6×1/8+1/2×3/4×5/6×7/8)
=1/2+1/2×1/4+1/2×3/4×1/6+[1/2×3/4×5/6×(1/8+7/8)]
=1/2+1/2×1/4+1/2×3/4×1/6+1/2×3/4×5/6×1
=1/2+1/2×1/4+1/2×3/4×1/6+1/2×3/4×5/6
=1/2+1/2×1/4+(1/2×3/4×1/6+1/2×3/4×5/6)
=1/2+1/2×1/4+[1/2×3/4×(1/6+5/6)]
=1/2+1/2×1/4+1/2×3/4×1
=1/2+(1/2×1/4+1/2×3/4)
=1/2+1/2×(1/4+3/4)
=1/2+1/2×1
=1/2+1/2
=1
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从后往前，先算后两个的和，再往前算
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