The final cache is located at:
N AB CD EFG
W HIJ KL MNO
Solve the following math problems to find the final cache location.
Main and 7th: 4(NE + SE) = AB
St. Joseph and 9th: NW - NE - SE = CD (C might be the digit 0)
St. Joseph and 6th: 20 x SW + NE + NW = EFG
Main and Mt Rushmore: NW x 5 - NE x 9 = HIJ
Main and 5th: NW + NE - 2 x SW + 10 = KL
St. Joseph and Mt Rushmore: 20 x NE + SE2 - 10 = MNO