Dedicated to anyone who's got an annoying little sister.

"Susan?"

"Yes?"

"What's six times four?"

"Twenty four."

Lucy scribbled it down.

The next day she asked,

"Susan?"

"Yes?"

"What's six times four?"

"Twenty four."

Lucy scribbled it down.

The next day she asked,

"Susan?"

"Yes?"

"What's six times four?"

"Twenty four. Why do you keep asking me that?"

"Because I keep giving my teacher my homework, and he tells me to try again."

Susan took the piece of paper.

"Lucy?"

"Yes?"

"What's six times six?"

"Twenty four."

"That's where you've gone wrong."