Responses from students:
- For 504k to be a perfect square, any number that allows 504k to be a perfect square can be the answer. e.g. sqrt(504x14) = 84, sqrt(504x126) = 252, sqrt(504x56) = 168
- There must be a pair of numbers like 2x2 for each different number an dsince they are 2^3, 3^3 and 7, they all can be multiplied like 2^4, 3^4 and 7^4 or 2^6, 3^6 and 7^6 to make a perfect square.