Daily Joke: Why this son says maths just doesn’t add up

A father and son were talking about the son’s failed maths test.

“Why did you fail your mathematics test?” the father asked.

The son answered: “On Monday, teacher said 3+5=8.”

“So?”

The son said: “On Tuesday, she said 4+4=8, and on Wednesday she said 6+2=8. If she can’t make up her mind, how do I know the right answer?”