Nonconstructive proof

A nonconstructive proof is like playing a guessing game where you know the answer, but you can't show how you got it. Let's say you want to prove that there is a certain toy in a room full of toys, but you don't know where it is. A constructive proof would mean that you go look for it and show me where it is. But a nonconstructive proof would mean that you tell me that the toy IS in the room, but you don't say where it is or how you know. You just say that it must be there because you know it can't be anywhere else. It's like you're using a process of elimination to show that the toy must be in that room, even if you don't know exactly where it is. Nonconstructive proofs are often used in math to show that something definitely exists or is definitely true, without the need to show exactly how it works or where it is.