Multiples

Question

Hi,

Given an integer number, output the sum of all the multiples of 3 and 5 below that number.
If a number is a multiple of both, 3 and 5, it should appear in the sum only once.

I actually solved the task, although there are probably better solutions. I tried to make the code more efficient with the else break but then the last test case fails. Why?

https://code.sololearn.com/cvFxl7Hx7GEA/?ref=app

Answer 1

my try, a very basic version:

limit = int(input())
res = 0
for num in range(1, limit):
if num % 3 == 0 or num % 5 == 0:
res += num
print(res)

Answer 2

GERAKULES

we do not need to run multiple *for loops*. just use one.

for ...

then use an if... elif... conditional

> check if number from the range is divisible evenly by 3
if yes: add number to s

> check if number from the range is divisible evenly by 5
if yes: add number to s

the issue in your code is, that a number like 15 is divisible by 3 and by 5, so both are added to the sum, since you run 2 loops.

Answer 3

GERAKULES Read the task description carefully: If the number is divisible by 3 as well 5, it should be counted only once.

Answer 4

You could use the filter function for example
https://code.sololearn.com/c1UO6j8pcwNG/?ref=app

Answer 5

Sonja

What about to this logic?

https://code.sololearn.com/c67652sosUua/?ref=app

Answer 6

A͢J What is your if-condition supposed to do? If a number is divisible by 3 AND 5, it is also divisible by 3 OR 5...?

Answer 7

Sonja
avoid using 'sum' as variable name. It is a python built-in method name and gave me a puzzling error when I tried to code an alternative solution beneath your code...😅

how about this?

num = int(input())
factors = []
for n in range(num):
if n%3==0:
factors.append(n)
elif n%5==0 and n not in factors:
factors.append(n)
#print(factors)
print(sum(factors))

Answer 8

My 15 pence:
s =sum( [n for n in range(15 ) if n%3*n%5==0])

Answer 9

Lisa

Yes so there should be i % 15 == 0:
But output will be same in both case

Answer 10

Lothar Is it a sololearn task? The task description in the thread read to me like "all numbers < input number"

Answer 11

Hi, guys! Explain to me what is wrong with this code? Please!

num = int(input())

s =0
for i in range(num):
a = i % 3
if a == 0:
s += i
for j in range(num):
b = j % 5
if b == 0:
s += j

print(s)

Answer 12

Thank you, Lothar for explanation.

Answer 13

Help me please. It doesn't work. Why?
https://code.sololearn.com/cYKdqQiXQw2k/?ref=app

Answer 14

Thank you, Lisa! :)