Same card number for addon card

[arpitium]

Hello,

I recently got HDFC infinia card along with addon card. The card details for the addon card is exactly the same (Card number, expiry and CVV).
1. Is this normal?
2. If I change the pin for primary card, is it also changed for addon card?
3. Will I be able to use it as a separate card in Amazon/Flipkart sale?

 

[NOOBY]

Update:
I got pp delivered to my regalia and both main and add on pp also having same numbers lol

the numbers are same both the name on card would be different. SO you can swipe them individually one after the other.