Base 9 to Base 10

Base 9

In base 9, each digit position represents a power of 9: the rightmost digit counts individual ones, the next counts groups of 9, the next counts groups of 9×9, and so on — the same place-value idea as base 10, just with 9 distinct digits instead of ten.

Base 10

Base 10 works the same way: the rightmost digit counts ones, the next counts groups of 10, the next counts groups of 10×10, and so on, using 10 distinct digits.