You can set the length for the nummber. If the value is greater than 1, then the number will be added to the left with zeros. If the value is 1, the number is displayed "as is".
For Example,

Number's length	Example
1	1, 3, 15, 125
3	001, 003, 015, 125
5	00001, 00003, 00015, 00125