# Learn How to Work With Numbers and Strings Using Luhn's Algortithm Step 19

``````def verify_card_number(card_number):
sum_of_odd_digits = 0
card_number_reversed = card_number[::-1]
odd_digits = card_number_reversed[::2]
**for variable in odd_digits:   **
**    print(variable)**

def main():
card_number = '4111-1111-4555-1142'
card_translation = str.maketrans({'-': '', ' ': ''})
translated_card_number = card_number.translate(card_translation)
verify_card_number(translated_card_number)

main()
``````

I’m not seeing how to correctly solve this. On the forums I’ve seen, this is the syntax I need to do the loop it’s asking me to do, but I don’t understand how to stop getting errors. Perhaps I need to define “variable?”

Hi there and welcome to our community!

For future reference: If you need help with a particular challenge, it is best to click on the Help button, which appears after you have submitted incorrect code three times.
This will create a forum post which automatically includes your full code, a direct link to the challenge and an opportunity for you to describe your issue in detail.

I have formatted your post so that your code displays correctly, and have included a link to the step.

Your code for this step is actually fine (once you remove the asterisks), as long as it is indented correctly. The `for` loop should be indented in line with the code directly above it, with the `print` command indented four spaces inside the `for` loop.
You can use the name `variable` if you wish, but it’s generally a good idea to use a name which relates to what you’re iterating (e.g. `digit`).

Thank you so much, this challenge was driving me crazy.

This is my first time using the help link and I couldn’t figure out how to make it pop up like you’re talking about, so thank you for that tip, too.

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