How to generate random numbers within a limit?

I am creating a war game, and I need the player's health to be 200, 300, 400, or 500. How can i do this? So far I only can generate numbers from 1 to 500:

set /a rndnum=%random% %%500+1

and I don't want that. I want to be able to generate numbers like 100, 200, 300, 400, or 500 only.