Final answer:
To find the markdown, subtract the final price from the original price. The original price was $100, the final price was $0.50, resulting in a markdown of $99.50.
Step-by-step explanation:
To calculate the markdown on an item, you need to subtract the final price from the original price and then compare that difference to the original price. In this case, the original price is $100 and the final price is $0.50.
The markdown is:
$100 - $0.50 = $99.50
Therefore, the markdown on the item is $99.50.