Disclaimer: I just finished grade 8 so I don't know a load about math. Okay, for this equation/expression to be solved at all, we must adhere to 2 rules/assumptions: Infinity (∞) is never ending and does not stop under any circumstances Subtracting anything from itself always equals zero Now for the equation that I can't solve: ∞-∞=x Solve for x. Now it may seem with rule 2 that the answer is zero. But rule 1 says that ∞ is never ending, no matter what is taken away. Even though you are taking away infinity from itself, it is still infinity because it never ends. Now that you see what I am thinking about this, you can see what I am thinking that could be an explanation: ∞ is not a number thus rule 2 does not apply Taking ∞ away from ∞ equals zero because rule 2 applies no matter how high the number Sorry if this is confusing, I'm cobbling this together as I type, hence the potential confusion. ...So can it be explained?