500
Given:
1 = 5;
2 = 25;
3 = 325;
4 = 4325;
What does 5 equal?
54325.....
Rather than being a mathematical solution, the answer is derived by prepending (putting in front of) the value on the left side of the equation with the previous answer. So for 3 you take 25, the previous answer, and put 3 in front, giving you 325. Then you put 4 in front to get 4325 and lastly, put 5 in front to get 54325.