Question 498087
There is no counterexample because -6 - (-2) is always -4. A counterexample would assert that there is a possibility that -6 - (-2) is not -4.


In general, a counterexample is a case where a theorem fails. For example, the statement "(2*3*5*7*11*...*p) + 1 is prime" has a counterexample where p = 13, because (2*3*5*7*11*13) + 1 = 59*509 and is therefore not prime.