Radical of an ideal

Okay kiddo, so let's say you have some numbers, and you want to find all the numbers you can multiply them by to get a whole number answer. That's kind of like what we call an "ideal".

Now, the "radical" of an ideal is all the numbers you can multiply together to get a number that's in the ideal. Kind of like finding all the grown-ups you have to talk to in order to get your way at home, haha.

So if we have the ideal {2, 4}, the radical would be {2}, because if you times 2 by any of those numbers, you get a whole number that's also in the ideal.

Does that make sense, little one?