in base

To decide if a number is divisible by your chosen number, start at **0**.
Then, do the following for each digit in your number: move along the **blue dotted line** from your current position, then move along as many **solid green arrows ** as the digit you're currently considering.
Note that the first dotted line, from the **0** space, leads back to **0**.
The number is divisible if you end up back at **0**.