Excel questions about formulas and negative numbers?

Im trying to set up a simple calculator with excel to help my users for my game i created. I have two questions.

Questions 1:

I am setting up a simple formula, for example, something like this =5000-B8. Lets say cell B8 has something higher than 5000, the answer shows a negative number. However, instead of negative numbers showing, I want to replace it with a word, or N/A. How do i set it up to where i can change the negative numbers into words?

Questions 2:

I want to set up a gradating answer for my users to show how close they are to achieving a merit. I'll give you an example. In the game, the user races so many miles. For each mile, it counts as a point. now, every 250 points the user collects, it gives the user a merit. I want to use excel to calculate how close the user is to another merit. Merits are earned every 250 points the user gains, and it does not reset. The limit the user can earn is 5000 points which means there are 20 merits the user can earn. How would i go about creating a guide to show how close the user is to the next available merit? Would you have to set up an If Then statement? If so, i need step by step instructions on how to do this...

example: The user has 1,317 points. So the next available merit would be at 1,500 points. So this is what the user puts into the cell on the excel spreadsheet:

User input: 1317

(answer) Next Merit in: 183 points