The expression $2n^2 - 2n^2$ simplifies as follows:

$2n^2 - 2n^2 = 0$

Since the two terms cancel each other out, the result is $0$.

Would you like more details or have any questions?

Here are some related questions you might find interesting:

1. What happens when you add two identical terms?
2. How do you factor common terms in algebraic expressions?
3. What is the result of subtracting any number from itself?
4. How can you apply this concept to more complex polynomials?
5. How does this relate to solving quadratic equations?

Tip: When two identical terms with opposite signs are combined, they always cancel out to zero.