1.) Below is the request for Step #12 of “learn-how-to-work-with-numbers-and-strings-by-implementing-the-luhn-algorithm” along with correct answer. When I then saw the directions for Step #13 I was confused. Should it not start with "Change `card_number_reversed`

" to confirm what variable needs to be updated like all previous steps?

2.) I then entered “card_number_reversed = card_number[11:16:-1]” as it states “You can use either negative or positive indices for the start and end indices.” I was told this was in error. You should have `card_number_reversed = card_number[-1:-5:-1]`

within the `verify_card_number`

function. Expected `--fcc-actual--`

to equal `--fcc-expected--`

.

Doesn’t this means I can only use Negative indices? Or should there be 2 possible answers, one using negative indices and one using positive indices?

# Step 12

Change `card_number_reversed`

to be every second digit of the first four digits of `card_number`

.

```
card_number_reversed = card_number[0:4:2]
```

# Step 13

Reverse the order of the digits in the last four digits of `card_number`

, by using a slice with a step of `-1`

. You can use either negative or positive indices for the start and end indices.