I found that when young they sometimes just need a some attention. If I was busy with something and one came to me wanting me to play with them, I’d say something like, “oh, I really need to do this but OK, let’s play for fifteen minutes and then I’ll go back to to my work.” Keep it positive like you want to play with them.
I might not even play for fifteen minutes if they are too young to tell time on their own. They often just need to be show that this person on whom they depend still cares to give them attention.