Binary Down Counter

How would I could a Binary Down Counter? I want it to go from 9-0. Is there any specific arduino code for binary? I would be very grateful if you could tell me, or link me to a help website or something. Thanks!

Bitread will help you.

You may be able to extract something from this. Post

How would I could a Binary Down Counter?

What does that mean? Do you want to see ones & zeros on a display? Do you want a string of 4 regular LEDs, with ones lit-up and zeros off?

The format only matters for input/output. The compiler doesn't care and the & chip only uses binary internally.