Answer:
To find a number that is both a perfect square and a perfect cube, we must solve x2 = x3 over x ∈Z+. The only two solutions to this equation are 0 and 1, or x = {0,1}. Therefore, zero and one are the only two numbers that are both perfect squares and perfect cubes.
--In easier terms: a perfect square is a number that can be "square rooted" and have no remainder. Like, 144. The square root is 12 therefore 144 is a perfect square. A perfect Cube is the same except that it must be "cubed rooted". Like 27. The cube root of this number is 3 therefore 27 is a perfect cube.