Steps followed:
1. Take natural number range as input from user
2. validate the range
3. add numbers in the range using loop
4. print the result

Program

#Python program to Find the Sum of Natural Numbers

# Take natural number range as input from user

range_lower_value,range_upper_value = input("provide the range in format lowerrange,upper range ").split(",")

total=0

#validate the range

try:

    range_lower_value = int(range_lower_value)

    range_upper_value = int(range_upper_value)

    if range_upper_value < range_lower_value:

        print("invalid range")

    else:

        for i in range(range_lower_value,range_upper_value+1):

            total=total+i

except:

    print("range provided is invalid")

#printing the result

print('Sum of Natural Numbers in range %d and %d is %d' %(range_lower_value,range_upper_value,total))

Output

provide the range in format lowerrange,upper range 0,10

Sum of Natural Numbers in range 0 and 10 is 55

 

provide the range in format lowerrange,upper range 50,100

Sum of Natural Numbers in range 50 and 100 is 3825

► Python program to Find the Sum of Natural Numbers