List of top Quantitative Aptitude Questions on Number System - Exponents and Perfect Squares

What is the difference between the sum of the cubes and that of the sum of the square of first twenty natural numbers?

If 'y' is a number such that \(y=x^{x/2}\), where x is a positive integer, what is the difference between the largest possible four-digit value of y and the smallest possible three-digit value of y?