> 1 + 1 will always equal 2, no one debates that.

Challenge accepted.

* In boolean algebra, 1 + 1 = 1

* Over the field Z2 (the integers modulo 2), 1 + 1 = 0

* In binary, 1 + 1 = 10

* In a language that allows overloading +, 1 + 1 = usually 2, but potentially almost anything else

In conclusion, context matters