A mark-up is calculated by percentage. So you'd say a 10% mark-up on ___

I am not 100% sure what your question is asking, but I think you are referring to selling an item to make profit. If you are talking about $USD, for example, you could say: - "The mark up on that TV is $100, they only bought it for $200." But normally we speak about a "mark-up" as a percentage - for example: - "The mark up on that TV is 50%." I hope that this helps, Tom