15 lines
308 B
Markdown
15 lines
308 B
Markdown
# 运算
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## 运算次序
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1. 括号
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2. 乘方、开方
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3. 乘除法
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4. 加减法
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## 巧算公式
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- $\dfrac{1}{n \times (n+1)} = \dfrac{1}{n} - \dfrac{1}{n+1}$
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- $\dfrac{d}{n \times (n+d)} = \dfrac{1}{n} - \dfrac{1}{n+d}$
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- $\dfrac{1}{n \times (n+d)} = \dfrac{1}{d} \times (\dfrac{1}{n} - \dfrac{1}{n+d})$
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