Python Program to Read a Number n And Print the Series "1+2+…..+n= "

When it is required to display the sum all the natural numbers within a given range, a method can be defined that uses a loop to iterate over the elements, and returns the sum of these numbers as output.

Below is a demonstration of the same −

Example

 Live Demo

def sum_natural_nums(val):    my_sum = 0    for i in range(1, val + 1):       my_sum += i * (i + 1) / 2    return my_sum val = 9 print("The value is ") print(val) print("The sum of natural numbers upto 9 is : ") print(sum_natural_nums(val))

Output

The value is 9 The sum of natural numbers upto 9 is : 165.0

Explanation

• A method named ‘sum_natural_nums’ is defined that takes a number as parameter.

• A sum value is defined as 0.

• A loop is iterated over the number passed as a parameter.

• The sum is incremented every time a number is encountered.

• This is returned as output.

• The value for number of natural numbers whose sum needs to be found is defined.

• The method is called by passing this number as a parameter.

• The relevant output is displayed on the console.