Inverse number in the range

Question

I have a servo that rotates against the number that I get from the program. The numbers that I get from the program are 37 ... 113. I need to translate 37 to the opposite side. Thus, 37 becomes 113, 38 becomes 112, etc. 75 remains at 75 because the midpoint.

Do any of you know a way to calculate this? It sounds like simple math, but I can't figure it out. I do not want to use a lookup table because the range may change.

Answer 1

public int reverseNumber(int num, int min, int max) { return (max + min) - num; } reverseNumber(37, 37, 113); // returns 113 

Answer 2

 public int calculate(int min, int max, int input) { return max-(min-input); }