Binary counting using 12 LEDs

What does it not take? As for right now, it is set to only take 00 - 99, as set by the limit. Since you only have 12 LEDs, you can only go as high as 4095, anything higher and it will automatically make it 4095. Unless you want rollover in which case you would need to add more code.

It's not about rollover. Imagine I insert 12, then 12 again, then I take a few seconds break. It stops everything and I have to start again from zero since it doesn't take any more input. Perhaps the little break might stop the key input. I don't think this is a big problem. Thanks for asking.

Here is why.

int number[]={ 0,0};

change it to,

int number[]={
  0,0,0,0};

You might be able to modify the code a little more, to where you can enter any number and have it count. So right now if limit is 1, you need to enter 2 digits. 0 2 => 2 or 1 9=> 19. But you can modify it so that if you press 5 # it should just add 5, without needing to enter 0 5. Its something you should be able to do on your own.

Thank you again I'm thinking already of a new challenging project. See you then. Regards