Wow!!! I'm so glad that Lil' Ms Pinky save my day by providing me the link to the answer of my son's question in my post Cold Monday. I never thought my son is kinda advance in his thinking. Hehehe..ya lah 4 years old only mah..and he can question us the parents..why this and why that. I don't remember myself asking my dad about this kind of thing last time. Maybe i stupid a bit lah, thats why never curious on why thing is like this, instead of that!!
So here is the Q&A i copy from yahoo..(the question exactly the same asked by son)..
And this is the answer given by...(do click the pix for better view)

I hope i'm able to use this explanation to make son understand why we use thirteen instead of 'threeteen' and 'fifteen' instead of 'fiveteen'.
Again..Thanx to lil' ms pinky for this info!!
