A card number is an alphanumeric unique code which always differs from each other. There may be many card numbers containing one, tow, three or more Zeros before 1, so by entering only 1 how shall it choose a card? An example is given below in order to make it more clear;
- 00001 : System Generated
- 000001 : User Defined
- 0000001 : User Defined
- 00000001 : User Defined
This is why you need to enter the full number.