a perfect cube is a natural number in the form
[tex] {a}^{3} = a \times a \times a[/tex]
therefore
[tex]{1}^{3} = 1 \\ {2}^{3} = 8 \\ {3}^{3} = 27 \\ {4}^{3} = 64 \\ {5}^{3 } = 125 \\ . \\ . \\ .\\ .[/tex]
and also you can define it as any natural number who's third root is also a natural number for examble
[tex] \sqrt[3]{1000} = 10[/tex]
so you can say that the tenth perfect cube is 1000