Fundamental coding help

Okay this is getting pretty petty of me, but I keep getting the impression that my approach isn't proper enough. It just seems somehow messy.

 Spoiler

[COLOR="red"]Given three ints, a b c, return true if one of b or c is "close" (differing from a by at most 1), while the other is "far", differing from both other values by 2 or more. Note: Math.abs(num) computes the absolute value of a number.

closeFar(1, 2, 10) → true
closeFar(1, 2, 3) → false
closeFar(4, 1, 3) → true[/COLOR]

Code:

public boolean closeFar(int a, int b, int c) {
  int diffAB = Math.abs(a-b);
  int diffAC = Math.abs(a-c);
  int diffBC = Math.abs(b-c);
  
  if((diffAB <= 1) && (diffBC <= 1) ||
     (diffAC <= 1) && (diffBC <= 1) ||
     (diffAB <= 1) && (diffAC <= 1))
    {
       return false;
    }
  else
    {
    if((diffAB >= 2) && (diffAC >= 2) && (diffBC >= 2))
       {
          return false;
       }
    else
       {return true;}
    }
}

I have a favor though, regarding this problem:

Given 3 int values, a b c, return their sum. However, if any of the values is a teen -- in the range 13..19 inclusive -- then that value counts as 0, except 15 and 16 do not count as a teens. Write a separate helper "public int fixTeen(int n) {"that takes in an int value and returns that value fixed for the teen rule. In this way, you avoid repeating the teen code 3 times (i.e. "decomposition"). Define the helper below and at the same indent level as the main noTeenSum().

noTeenSum(1, 2, 3) → 6
noTeenSum(2, 13, 1) → 3
noTeenSum(2, 1, 14) → 3

The solution should be simple enough, but I can't seem to "call" the n from the fixTeen block to the main block to use. Also, I may not be thinking straight but how do I filter so that the outcome n satisfies certain conditions? I have been doing something along the lines of conditionals:

Code:

public int fixTeen(int n){
  if( (n>=13) && (n<=19) && (n != 15) && (n != 16) )
  return n;
}

But I can't test if it works correctly because of the problem above.