Let’s say you want to delete–oh, I don’t know–let’s say a random 7% of all particles, and you want to do that every N frames. Here’s one way to do it. You won’t get exactly 7%, but you’ll get close (eg I got numbers like 6.8%, 7.2%, and 7.25% when I tested it).

The Every Nth Frame compound is a custom compound that uses modulo: