In my WIP, both the folk of Tesra and my two visiting wizards from the lost (in another world) city of Hirstel are accustomed to using a Base Twelve system of numbers. The wizardess Na found the Base Ten system of the Ildin, with whom she had spent the previous months, terribly cumbersome and couldn't imagine why they used it. Both Tesra and Hirstel were founded by refugees from the valley of the Tez (aka the Valley of Visions), which explains their shared numbers (as well as culture and ethnicity). I suppose none of that really matters any to the story, aside from having somewhat subtle influences on cultural practices, such as the calendar used, the currency, the size of army units (with troops, naturally, of 144 men—or '100' in their system). All this is buried in the world building and rarely mentioned in the narrative of the story itself. I'm never quite sure how much of that sort of thing to pass on to the reader, to help flesh out the world I have created, and how much just gets in the way. Of course, I could go on endlessly about such things were I to permit myself! Incidentally, the ancient Sharshites (who were still wandering tribes known as Charcha at the time of this book), employ a Base Five system of numbers, allowing an abacus-like use of their fingers, counting to five on one hand and then by fives up to 25 on the other. I haven't put that into a story yet and maybe never will, but I am aware of it. I've even invented the numerals, which may show up as a relic of olden days in some tale or another. I've not seen much of this in stories, though alternative number systems abound around the world. Five, ten, twelve, twenty, etc. Some of the choices are bewildering—just how did a culture choose such a number as their base? I'm wondering whether to bother incorporating more of this sort of thing, if only behind the scenes, i.e. mostly for my own information. What of creatures with a different number of digits? Would cartoon characters use Base Eight, counting on their fingers? No real question in all of this, I guess, just wondering whether and how others incorporate (or ignore) such things. Perhaps just dealing with different languages and manners is enough!