Is ka matlab hai jab ap series buy kro tu check krlo k 1 to 100 numbers pure han, coz sometimes seller jo ha wo ap se pehle draw check krke prized bonds nikal ke unhei random numbers se replace krdeta hai, or jab ap beth k check krte ho tu apko jab pata chalta ha k yeh number hi gayab hai. Ya seller ne ussi number ka OLD BOND daldia ha, jo eligible ni prize k lye , so try to make sure series is complete.
Also to be a good player keep switching your bonds with the seller, if you think that you are not getting any prize out from this series. If you buy 4 to 5 series probability of atleast getting a prize gets really high, and keep a good relation with the bond seller, he sometimes know which series have high probability of a prize.
As ap Karachi se hi ho, tu jo old State Bank hai us k back gate k samne ik choti si gali hai, uske andar puri market ha buy krne hon tu wahan se krna, don't buy from those guys sitting infront of Police station on the street.