Little Johnny

Teacher: If I gave you 2 cats and another 2 cats and another 2, how many will you have?

Johnny: Seven, Sir.

Teacher: No, listen carefully.

If I gave you 2 cats, and another 2 cats and another 2, how many will you have?

Johnny: Seven

Teacher: Let me put it to you differently.

If I gave you 2 apples, and another 2 apples and another 2, how many will you have?

Johnny: Six.

Teacher: Good. Now if I gave you 2 cats, and another 2 cats and another 2, how many will you have?

Johnny: Seven!!!

A very angry Teacher: Where in the hell do you get seven from?!?!?

A very angry Johnny: Because ...

Spoiler:

I've already got a cat !