## Problem Explanation

- In this challenge we need to find sum of all prime numbers up to
`n`

.
- Example:
- If
`n = 10`

then prime numbers before it are `2, 3, 5, 7`

and their sum is `17`

.

- We’ve used Sieve of Eratosthenes algorithm to find prime numbers in the below solution.

## Solutions

## Solution 1 (Click to Show/Hide)

```
function primeSummation(n) {
// Initializing the array and sum which hold all prime numbers and the total sum, respectively
let nums = []
let sum = 0;
// Upperbound of `n`
const upperBound = Math.ceil(Math.sqrt(n));
// Making an array of `n` numbers
for (let i = 0; i < n; i++){
nums.push(i);
}
nums[1] = 0;
// Looping until the upperbound
for (let i = 2; i <= upperBound; i++){
// Skipping if the number is already 0
if (nums[i] !== 0){
// Explcitly marking all multiples of `i` 0
for (let j = i*i; j < n; j += i){
if (nums[j] % i == 0) {
nums[j] = 0;
}
}
}
}
// Sum and return all values in the array up to `n`
for (let i = 0; i < n; i++){
sum += nums[i];
}
return sum;
}
```

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