If two plus two equal fish then what does four plus four equal?

If you overlay a 2 with a backward 2, it looks like a fish swimming upward (moreso when turned sideways).

As shown on the TV series called The Fairly Oddparents, a character wishes that he was always right. The wish is granted and when the teacher asks him what 2 + 2 is, he said "Fish" and everyone then believed that "fish" was the correct answer.

There is one more possible way of looking at this. here's how it goes: 2+2=4, and there are four letters in the Word "fish". Another example: 3+2= z e b r a. there are five letters in zebra.