# Sum of the series 5+55+555+.. up to n terms

Find the sum up to n terms of the sequence: 5 + 55 + 555 + … up to n.
Examples :

```Input : 2
Output: 60

Input : 3
Output: 595
```

## Recommended: Please try your approach on {IDE} first, before moving on to the solution.

Approach:The above problem can be solved using the following formula:

Sum = 5 + 55 + 555 + …. n terms.
= 5/9[9 + 99 + 999 + …. n terms]
= 5/9[(10 – 1) + (100 – 1) + (1000 – 1) + … n terms]
= 5/9[10 + 100 + 1000 ….. – (1 + 1 + … 1)]
= 5/9[10(10n – 1)/(10 – 1) + (1 + 1 + … n times))
= 50/81(10n – 1) – 5n/9

Below is the Implementation to find the sum of given series:

## C++

 `// C++ program for sum of the  ` `// series 5 + 55 + 555.....n ` `#include ` `using` `namespace` `std; ` ` `  `// function which return the ` `// the sum of series ` `int` `sumOfSeries(``int` `n) ` `{  ` `    ``return` `0.6172 *  ` `           ``(``pow``(10, n) - 1) - ` `                    ``0.55 * n;  ` `     `  `} ` ` `  `// Driver code ` `int` `main() ` `{ ` `    ``int` `n = 2;  ` `    ``cout << sumOfSeries(n); ` `    ``return` `0; ` `} `

## Java

 `// Java program for sum of the  ` `// series 5 + 55 + 555.....n ` ` `  `class` `GFG  ` `{ ` ` `  `    ``// function which return the ` `    ``// the sum of series ` `    ``static` `int` `sumOfSeries(``int` `n) ` `    ``{ ` `        ``return` `(``int``) (``0.6172` `*  ` `                     ``(Math.pow(``10``, n) - ``1``) - ` `                                ``0.55` `* n); ` `    ``} ` `     `  `    ``// Driver code ` `    ``public` `static` `void` `main(String []args) ` `    ``{ ` `        ``int` `n = ``2``; ` `        ``System.out.println(sumOfSeries(n)); ` `    ``} ` `} ` ` `  `// This code is contributed by UPENDRA BARTWAL. `

## Python3

 `# python program for sum of the  ` `# series 5 + 55 + 555.....n ` ` `  `def` `sumOfSeries(n): ` `    ``return` `(``int``) (``0.6172` `*`  `                 ``(``pow``(``10``, n) ``-` `1``) ``-` `                        ``0.55` `*` `n) ` ` `  ` `  `# Driver Code ` `n ``=` `2` `print``(sumOfSeries(n)) ` ` `  `# This code is contributed  ` `# by Upendra Singh Bartwal `

## C#

 `// C# program for sum of the ` `// series 5 + 55 + 555.....n ` `using` `System; ` ` `  `class` `GFG  ` `{ ` ` `  `    ``// Function which return the ` `    ``// the sum of series ` `    ``static` `int` `sumOfSeries(``int` `n) ` `    ``{ ` `        ``return` `(``int``)(0.6172 *  ` `                    ``(Math.Pow(10, n) - 1) - ` `                                 ``0.55 * n); ` `    ``} ` `     `  `    ``// Driver code ` `    ``public` `static` `void` `Main() ` `    ``{ ` `        ``int` `n = 2; ` `        ``Console.Write(sumOfSeries(n)); ` `    ``} ` `} ` ` `  `// This code is contributed by vt_m. `

## PHP

 ` `

Output :

```60
```

code