Little Johnny failed his math test

Little Johnny failed his math test dismally.

His mark was so bad, his teacher called home to have a word with his dad.

When he returned home that afternoon, his father was standing crossly in the doorway.

“Why did you fail your math test?” he asked.

Little Johnny shrugged and said:

“My teacher isn’t very good.”

His father was surprised by his excuse and asked Johnny to elaborate.

“Well, on Monday, my teacher said 3+5 = 8.”

“So?” his father answered.

“Then on Tuesday, she told us 4+4 = 8, and on Wednesday she said 6+2 = 8,” explained the boy.,

“If she doesn’t know what equals eight, how am I supposed to know the right answer?”