Another Simple Mathematics

Teacher: If I give you 2 cats and another 2 cats and another 2 cats, how many cats will you have?
AKPOS: Seven, Sir.
Teacher: No, listen carefully. If I gave you 2 cats, and another 2 cats and another 2 cats, how many will you have?
AKPOS: Seven.
Teacher: Let me put it to you differently. If I give you 2apples, and another 2 apples and another 2 apples, how many will you have?
AKPOS: Six.
Teacher: Good! Now if I gave you 2 cats, and another 2cats and another 2 cats, how many cats will you have?
AKPOS: Seven!!!
Angry Teacher: Where did you get ur seven from?
AKPOS: (Angrilly!) Because I already have 1 cat at home!