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FAQ: Code Challenge: Python Functions - First Three Multiples

This community-built FAQ covers the “First Three Multiples” exercise from the lesson “Code Challenge: Python Functions”.

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This exercise can be found in the following Codecademy content:

Data Science

FAQs on the exercise First Three Multiples

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Write your first_three_multiples function here:

def first_three_multiples(num):
print(num)
print(num2)
print(num
3)
return num*3

Uncomment these function calls to test your first_three_multiples function:

first_three_multiples(10)

should print 10, 20, 30, and return 30

first_three_multiples(0)

should print 0, 0, 0, and return 0

On the above code, I am not sure why the 5th line line, " return num*3 " is necessary, when you run the function, it returns, 10,20,30.

I found this one to be an odd exercise. I knew while completing it that there were better ways to write the function, but couldn’t think of anything except for the following:

Write your first_three_multiples function here:

def first_three_multiples(num):
print(num, num + num, num + num + num)
return num + num + num

Running this worked and met the requirements to complete this portion of the lesson, but for practical application, how could I write this better? For example, how would I write this function if I wanted to see the first 50 multiples and have it return or print the 27th, 32nd and 50th? My solution above would still work but would require a LOT of "+ num"s. Obviously the better choice is to keep your code as simple and condensed as possible.

I feel silly asking but for some reason I’m not connecting the dots on this one…

Returning three values implies a list, or a tuple sent back to the caller.

return num, num * 2, num * 3

Given that as a return value, we can use the unpack operator on either list or tuple.

>>> def first_three_multiples(x):
	return x, x * 2, x * 3

>>> first_three_multiples(10)
(10, 20, 30)
>>> print (*first_three_multiples(10), end=' ')
10 20 30 
>>> 
>>> def first_three_multiples(x):
	return [x, x * 2, x * 3]

>>> print (*first_three_multiples(10), end=' ')
10 20 30 
>>> 

The lesson expects only a single value on return, the third multiple, and for us to print the values in the loop.

for x in range(num, num * 4, num):
    print (x, end=' ')
return x

Absolutely no reason to feel silly! We’re all learning here!

Instead of writing

def first_three_multiples(num):
print(num, num + num, num + num + num)
return num + num + num

you can just use a num, a num*2, and a num*3 (Also return num*3)
Like this

def first_three_multiples(num):
print (num)
print (num*2)
print (num*3)
return num*3

Multiplying is just simplified addition, so here we can just use multiplying and be neat and simple - instead of adding all of them.

How do we ‘simplify addition’? Multiplication is repeated addition and only exists because of the additive property of numbers.

You’re completely right, I did mean repeated! My apologies, it was pretty late when I replied to that, didn’t completely get to convey my thoughts haha.
But yeah, the code should still be correct, regardless of my language barrier blunder.
(When I said simplified, I meant less items in code, replying to their question on how to keep code “as simple and condensed as possible.”)
Thanks for the keen eye!

1 Like

Issue with the UI. I uncommented the (10) and got the correct answer BUT the UI complains that I should have returned 15.
See screenshot
Google Photos

wait, there’s more! It gets better/worse… I supply the ‘correct answer’ and the UI still complains that it returned 15 and expected 15!
Google Photos

1 Like

Is there a reason to be casting everything to str? print() can handle numbers just fine, and we should be returning a number to the caller, not a string.

Yep. Good point re: str(print). You are right. It is unnecessary.
I have been doing a lot of formatting str and num in sentences, I got carried away.

1 Like

This can be helpful when dealing with more of these properties in the future:

def first_three_multiples(num):
  for m in (1,2,3):                            #loops the next line for each variable in m
    print(num*m)
  return num*3

had this problem as well. nothing i did would let me clear it. quite frustrating

hello could someone explain if “return num3" is necessary? I remove them from the syntax, it works still, is there any reason why this "return num3” exist in solution?

thank you

The instructions for the function specify that it should “return the third multiple.”

If your code has passed one time, the “Next” box will remain highlighted and receptive to a click no matter what you subsequently type. But if you first click the “Reset Exercise” icon (located next to “Run”) and then type in the code without the return statement, it will not pass.