I've always hated exponents but the way I visualize this is essentially taking 5^4 and multiplying it by itself 3 times (because it is put to the power of 3).
(5^4)·(5^4)·(5^4)
when you do this you can just add the exponents together
multiply the exponent of 4 to exponent of 3, so its equal to 5^12 since this is law of a product of product. It says that SIMPLIFY so, you have to answer the 5^12 into simplest form which is 244,140,625
