Blue Prince - Numeric Core Calculator

Late-game in Blue Prince you'll discover the concept of a "Numeric Core" in a specific note left by a certain foreman. The concept is to take any 4 or 5 digit number and perform a series of mathmatical operations on it to derive a smaller number. This can also be done with 4 letter words to derive a new letter. If you want to pass in 4 specific numbers to get a numeric core (instead of defaulting to splitting a whole number into 4), separate them by spaces or commas.