Solution: Let $a + b = 2025$. The greatest common divisor $\gcd(a, b)$ must divide $a + b = 2025$. The maximum possible value of $\gcd(a, b)$ occurs when $a$ and $b$ are both multiples of the largest divisor of 2025. Since $2025 = 45^2 = 3^4 \cdot 5^2$, its largest proper divisor is $2025 / 3 = 675$. Thus, $\gcd(a, b) = 675$ when $a = 675$ and $b = 1350$. - Abu Waleed Tea