Little Johnny's teacher asks him, "If I gave you two cats, then two more, and two more cats; how many would you have?"

Little Johnny replies, "Seven!"

His teacher asks him again more slowly, "If I gave you two cats, then two more, and two more cats; how many would you have?"

But again Little Johnny replies, "Seven!"

Next she asks, "If I get two cats, then two more, and two more cats; how many would I have?"

Little Johnny replies, "Six!"

"Good Job Johnny! Now if I gave you two cats, then two more, and two more cats; how many would you have?"

Johnny thinks for a second, "Seven."

But Johnny is not wrong. Why?