    # How do you add numbers from 1 to n in python?

I'm trying to write a program to add up number from 1 to n. I've managed to get it to print the numbers several times but not add them all. It keeps on just adding two of the numbers.

My 1st attempt is:

``````def problem1_3(n):
my_sum = 0
# replace this pass (a do-nothing) statement with your code
while my_sum <= n:
my_sum = my_sum + (my_sum + 1)
print()
print(my_sum)
``````

How can I fix this problem?

asked May 10, 2017 at 19:45

3

I don't understand why everyone keeps making everything complex. Here is my simple solution

``````n = int(input())
print(n * (n + 1) // 2)
``````

answered Feb 22, 2020 at 3:41 Akshat TamrakarAkshat Tamrakar

2

You can do it with one line, where you create a list of integers from `0` to `n` and sums all the elements with `sum` function

``````def problem1_3(n):
return sum(range(n+1))
``````

answered May 10, 2017 at 19:57

3

That's where I use "math" to solve problems like this. There is a formula for solving this problem: n * (n+1) / 2.

The code I would write:

``````def sum(n):
return n*(n+1)//2
``````

answered Jun 3, 2021 at 12:42 ahmedgahmedg

You need 2 different variables in your code -- a variable where you can store the sum as you iterate through the values and add them (my_sum in my code), and another variable (i in my code) to iterate over the numbers from 0 to n.

``````def problem1_3(n):
my_sum = 0
i=0
#replace this pass (a do-nothing) statement with your code
while i <= n:
my_sum = my_sum + i
print(my_sum)
i+=1
return my_sum
``````

You are using the my_sum variable in your code to both store the sum and iterate through the numbers.

ayhan

answered May 10, 2017 at 20:23

0

This one line do the job :

``````sum(range(1, n+1))
``````

answered Feb 8, 2018 at 14:04

answered Oct 24, 2018 at 13:27

The sum of numbers from 1 to n will be greater than n. For example, the sum of numbers from 1 to 5 is 15 which is obviously greater than 5. Your while loop terminates prematurely. You need to maintain a separate counter for the loop.

answered May 10, 2017 at 20:14

HeshamHesham

Actually, I have tried a lot of that type of Programs In Jupyter Notebook you may use these:

``````n = int(input("Enter the Number: "))
print(n * (n + 1) // 2)
``````

And Also You may try this code:

``````def problem1_3(n):
return n + problem1_3(n-1) if n > 1 else 1
``````

And Also You may try it

``````def f(a):
return (a + 1) * (abs(a) + 2 * (a <= 0)) // 2
``````

answered Dec 10, 2020 at 16:41 Real programmers use recursion (and hopes for a not too big n since there is no tail call optimization in Python):

``````def problem1_3(n):
return n + problem1_3(n-1) if n > 1 else 1
``````

answered May 10, 2017 at 20:28

JohanLJohanL

1

so it will be more optimal

``````def f(a):
return (a + 1) * (abs(a) + 2 * (a <= 0)) // 2
``````

answered Sep 11, 2018 at 9:26

yoloyyoloy

1

``````print("Sum =",sum(range(int(input("Enter a number\n"))+1)))
``````

answered Oct 24, 2018 at 12:55

1

THIS WHILE LOOP ACTUALLY WORKS:

def main():

``````n = int(input('Enter a number:'))

while n <= 1:
n = int(input('Please input a new number'))

total = 0
my_sum = 0
while (n - 1) >= total:
total = total + 1
my_sum += total
print(my_sum)

return
``````

main()

answered Mar 8, 2021 at 3:20

1

These lines worked for me in Python

``````def summation(num):
sumX = 0
for i in range(1, num + 1):
sumX = sumX + i
return sumX

summation(3) #You place the num you need here
``````

As well as these:

``````def summation(num):
return sum(range(1, num+1))

summation(3) #You place the num you need here
``````

answered Jul 10, 2021 at 22:40

How about you try it using a "While Loop":

``````def problem1_3(n):
my_sum = 0
while my_sum <= n:
print(my_sum,end=" ")  # end = " " keeps from starting a new line
my_sum = my_sum + 1
print(my_sum)
``````

answered Jun 28, 2017 at 12:15 ``````n = input("Enter Number to calculate sum")
n = int (n)
#average = 0.
#sum = 0
sum = 0.
for num in range(0,n+1,1):
sum = sum+num
print("SUM of first ", n, "numbers is: ", sum )

# Print sum of numbers from 1 to N inclusive

def sum2N(N):
r = 0
for i in range(N+1):
#for i in range(0,N+1,1):
#r+=i
r=r+i
return(r)

print(sum2N(10))
``````

answered Apr 29, 2019 at 9:04

### How do you add a number from 1 to n?

The formula of the sum of first n natural numbers is S=n(n+1)2 .

### How do you add all the numbers from 1 to 10 in Python?

“print sum of all the numbers 1 to 10 in python using for loop” Code Answer's.
n = input("Enter Number to calculate sum").
n = int (n).
sum = 0..
for num in range(0, n+1, 1):.
sum = sum+num..
print("SUM of first ", n, "numbers is: ", sum ).

### How do you add n numbers in Python?

See this example:.
num = int(input("Enter a number: ")).
if num < 0:.
print("Enter a positive number").
sum = 0..
# use while loop to iterate un till zero..
while(num > 0):.
sum += num..

### How do you sum a range of numbers in Python?

To sum all numbers in a range: Use the range() class to get a range of numbers. Pass the range object to the sum() function. The sum() function will return the sum of the integers in the range. 