A math argument

Rachael came to me this morning and said, "We're having a little argument, so we need to ask you a question."

"Yes?" I said.

"What is one hundred plus twelve?"

"Hmm ... well, first you tell me what you each say."

One girl said, "One hundred twelve!"

And the other girl said, "One hundred and twelve!"

I said, "Guess what? You're both right! That's two different ways of saying the same number!"