When does 2 plus 2 equal 11?

Answer 1

2 plus 2 can equal 11 when you are counting in base 3. However, as it is not expressed in a decimal base, this answer would not be read "eleven" but "one one".

Answer 2

In a binary system, where only the digits 0 and 1 are used, the addition of 2 (represented as 10 in binary) and 2 (also represented as 10 in binary) equals 100 in binary, which is 4 in the decimal system. Therefore, in this specific context, 2 plus 2 equals 11.