Abstract object theory is like playing pretend with things that don't really exist. Just like how you can pretend to be a princess or a superhero, we can pretend that things like numbers or ideas are real even though we can't touch them or see them.
For example, you know what the number 5 means even though you can't hold it in your hand. It's an idea or concept that we use to help us count things. People who study abstract objects are interested in understanding how these things work and how we can use them to help us better understand the world around us.
Think of it like a big puzzle - we try to fit all the pieces of our knowledge about abstract things together to make sense of the world. We might not always have all the answers, but we keep searching and asking questions.
In short, abstract object theory is like using our imagination to think about things that aren't real but help us understand how real things work.