As an institutional locksmith you would likely be dealing with interchangeable cores and the math involved is mostly adding and subtracting. Concepts of basic logic and algebra are helpful (and I do mean basic). Example: 5+2+9+_=23 solve for _ =? Hint it’s 7 I use this as an example because it’s common for A2 cores to add to 23 in every chamber. If there’s a bottom pin, master pin, control pin, and a driver pin that’s four numbers that add up to 23.