0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, 10, 11, 13, 14, 15, 16, 17, 18, 19, 1A, 1B, 20, 21, …, A0, A1, A3, …

You can use your hands to count in base 12 if you want to, and some cultures have done so. Just use the segments on your fingers on one hand, using your thumb to count each segment.

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