Problem 6: Sum square difference
Problem Explanation

Sum of first n natural numbers can be calculated by using this formula:

Sum of squares of n natural numbers can be calculated by using this formula:

We can calculate the values using the above formula and subtract them to get the result.
Solutions
Solution 1 (Click to Show/Hide)
function sumSquareDifference(n) {
const sumOfN = (n*(n+1))/2;
const sumOfNSquare = (n*(n+1)*(2*n+1))/6;
//** is exponentaial operator added in ES7, it's equivalent to Math.pow(num, 2)`
return (sumOfN ** 2)  sumOfNSquare;
}