# [Tutor] Fwd: im having problems and need help

Leam Hall leamhall at gmail.com
Wed Sep 20 15:15:41 EDT 2023

```Hey Robert, no worries!

If I am using whole numbers for division, like 3, and 20, then:
20 divided by 3 gives 6.
3 times 6 is 18, and if I am dividing into 20, there is 2 left over.

So, 20 % 3 is 2, since there is 2 left over.

When you say:
if number % 2 == 0:
You have already proven that the number is even.

Does that help?

Leam

-------- Forwarded Message --------
Subject: 	Re: [Tutor] im having problems and need help
Date: 	Wed, 20 Sep 2023 12:03:12 -0700
From: 	Robert Towne <townerobert1 at gmail.com>
To: 	Leam Hall <leamhall at gmail.com>

I'm lost on the modelo. % it's a reminder? I don't understand it. I ran it in print(number%2). No matter what the number was it would come out to 1 or 0. I'm thinking the % is like a pre program. If it's even or odd. I'm not sure. Though. I'm stuck.
I can run a while loop. But I'm lost at this modulo %.

On Wed, Sep 20, 2023, 4:48 AM Leam Hall <leamhall at gmail.com <mailto:leamhall at gmail.com>> wrote:

Robert,

Sorry, your mail program killed the code indents. Also, "%" is the modulus/modulo operator, not the power.

>>> 20 % 2
0

So, the while line:
number % 2 == 0

Returns True if number is even. It says "If number / 2 leaves no remainder". Compare that to:

>>> 20 % 3
2

Which says "20 / 3 leaves a remainder of 2".

Hope that helps.

Leam

On 9/15/23 15:07, Robert Towne wrote:
> Im having problems understanding this. Im running the while loop like it
> says; and it doesnt complete the loop.
> My question is, is it the formula thats wrong or my math. The % sign means
> to square the number?
> since i the to the second power is 64. Then it should return false. IDK
> what I am doing wrong, if you could
> help me understand where I am going wrong i would appreciate it thank you.
>
> def is_power_of_two(number):
> # This while loop checks if the "number" can be divided by two
> # without leaving a remainder. How can you change the while loop to
> # avoid a Python ZeroDivisionError?
> while number % 2 == 0:
> number = number / 2
> # If after dividing by 2 "number" equals 1, then "number" is a power
> # of 2.
> if number == 1:
> return True
> return False
>
> # Calls to the function
> print(is_power_of_two(0)) # Should be False
> print(is_power_of_two(1)) # Should be True
> print(is_power_of_two(8)) # Should be True
> print(is_power_of_two(9)) # Should be False
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