# Sum of Natural Numbers Using Recursion

In this example, you’ll learn to find the sum of natural numbers using recursion. To solve this problem, a recursive function calculate_sum() function is created.

To understand this example, you should have the knowledge of following R programming topics:

## Example: Sum of Natural Numbers

```
# Program to find the sum of natural numbers upto n using recursion
calculate_sum() <- function(n) {
if(n <= 1) {
return(n)
} else {
return(n + calculate_sum(n-1))
}
}
```

**Output**

> calculate_sum(7) [1] 28

Here, we ask the user for a number. The number entered by the user is passed to `calculate_sum()`

recursive function which computes the sum up to that number.