19 lines
329 B
Markdown
19 lines
329 B
Markdown
---
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title: sumN
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tags: math,beginner
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firstSeen: 2020-10-08T16:52:55+03:00
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lastUpdated: 2020-10-22T20:24:30+03:00
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---
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Sums all the numbers between `1` and `n`.
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- Use the formula `(n * (n + 1)) / 2` to get the sum of all the numbers between 1 and `n`.
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```js
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const sumN = n => (n * (n + 1)) / 2;
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```
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```js
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sumN(100); // 5050
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```
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