729
343 7*7=49 49*7=343
27, whose cube is 19683
125
I am pretty sure you can figure this out on your own. Raise different numbers to the square, until you get a 4-digit result. Similary, calculate the cube of different numbers, until you get a 4-digit number. If you want the SAME number to be both a perfect square and a perfect cube, then it must be a power of 6. In that case, just experiment raising different numbers to the sixth power, until you get a 4-digit number.
729
729
729, cube of 9 and square of 27
46*46*46 = 97336
I believe there are 2 positive three-digit perfect cube numbers, that are even.
729
343 7*7=49 49*7=343
27, whose cube is 19683
It doesn't matter if you know that the largest three-digit prime number is 997 or that its cube root is 9.98998998. If you include zero in the whole numbers, the answer will be zero.
8
125
I am pretty sure you can figure this out on your own. Raise different numbers to the square, until you get a 4-digit result. Similary, calculate the cube of different numbers, until you get a 4-digit number. If you want the SAME number to be both a perfect square and a perfect cube, then it must be a power of 6. In that case, just experiment raising different numbers to the sixth power, until you get a 4-digit number.