Change output values of part of an array

Hello
I have a multipad of 12x3

The first row of 12 should put out a value of 1+increment of 1
The second row should output 100+increment of 1
The third row should output 1000+increment of 1

How do I do this? I tried something like:

decl i;
i=firstof(Pads.x);
if (Pads.x)>=12)num=100++;

But this didn't work

Thanks!

Obviously I'm missing the part about how to address a part of an array and how to reset the increment back to 0 when the array changes