what to call the numbers
numbers up to twelve (20) can keep their usual names.
0 "zero", 1 "one", 2 "two", 3 "three", 4 "four", 5 "five",
10 "six", 11 "seven", 12 "eight", 13 "nine", 14 "ten", 15 "eleven",
20 "twelve"
after twelve, I originally suggested "twelve one, twelve two" and so on, but that sounds kinda awkward, so instead what you do is use the OTHER word we already have for two sixes, "dozen":
20 "twelve", 21 "dozen one", 22 "dozen two", 23 "dozen three", 24 "dozen four", 25 "dozen five"
after that, we need to make new words for larger multiples of six. I decided to adapt the -ty suffix used for multiples of ten into a -sy suffix, resulting in the words "thirsy", "foursy", and "fifsy".
30 "thirsy", 31 "thirsy one", 32 "thirsy two", 33 "thirsy three", 34 "thirsy four", 35 "thirsy five"
40 "foursy", 41 "foursy one", 42 "foursy two", 43 "foursy three", 44 "foursy four", 45 "foursy five"
50 "fifsy", 51 "fifsy one", 52 "fifsy two", 53 "fifsy three", 54 "fifsy four", 55 "fifsy five"
how about 100 then? for 100, I wanted to pay homage to the people who have been using seximal this entire time. specifically, I used the word for six sixes found in the Ndom language, "nif".
100 "nif", 101 "nif one", 102 "nif two", 103 "nif three", 104 "nif four", 105 "nif five",
110 "nif six", 111 "nif seven", 112 "nif eight", 113 "nif nine", 114 "nif ten", 115 "nif eleven"
oh, by the way, if you want, you can call 110 "sevensy", much like how you can call 302 (eleven tens) "eleventy" in decimal. it isn't like the proper way of saying it, but it works fine. same goes for 120 "eightsy", 130 "ninesy", 140 "tensy", and 150 "elevensy".
next, multiples of nif work in the obvious way.
100 "nif", 200 "two nif", 300 "three nif", 400 "four nif", 500 "five nif"
1000 "six nif", 1100 "seven nif", 1200 "eight nif", 1300 "nine nif", 1400 "ten nif", 1500 "eleven nif"
notice that six cubed is just called six nif. this allows you to easily think of seximal numbers in pairs of digits, making niftimal compression as easy to understand as possible. if you want, you can call six nif "tarumba", a loan from the Kómnzo language, but that should only be used when you're talking about round multiples of six nif. 4321 "four tarumba three nif dozen one" sounds a bit clunkier than "foursy three nif dozen one".
this gets you up to 5555 (fifsy five nif fifsy five), but we're not done yet! what about larger powers of six? what's the seximal version of the thousand-million-billion series?
1 0000 is called "unexian". 1 0000 0000 is called "biexian". 1 0000 0000 0000 is "triexian". as you probably figured out, [some graecolatinish number root]-exian means 1 0000 to the power of that number. all that's left is to determine exactly which graecolatinish number roots to use. I mean, you don't need to do that because I already did that and here they are!
1 - unexian
2 - biexian
3 - triexian
4 - quadexian
5 - pentexian
10 - unnilexian
11 - ununexian
12 - umbiexian
13 - untriexian
14 - unquadexian
15 - umpentexian
20 - binilexian
so, basically, the digits 0 through 5 are called "nil", "un", "bi", "tri", "quad", and "pent", and you just say the digits of the power of unexian separately. do note, however, that "un" becomes "um" before "bi" or "pent", and that "pent" and "quad" become "penta" and "quada" before "nil", "bi", "tri", "quad", or "pent".
for non integers, there's a few options. the simplest one is to just say the digits after the seximal point separately. this is most useful when you're talking about irrational numbers, or other numbers whose values have been significantly rounded. for example, 10.1411 (~the ratio of a circle's circumference to its radius) is "six point one four one one". if you want, you can group it into two digit pairs, as in "six point ten seven".
for numbers with only one digit after the seximal point, it's usually best to say the exact fraction it corresponds to: 1.1 "one and a sixth", 1.2 "one and a third", 1.3 "one and a half", 1.4 "one and two thirds", and 1.5 "one and five sixths". the ordinal/fractional versions of the new words used for seximal work the same way as they do for other numbers: thirsy/thirsieth, nif/nifth, unexian/unexianth, etc.
finally, and most interestingly, numbers between zero and one can be expressed in pernif form, which is the seximal version of percentages. 13% "nine pernif" is a fourth, 30% "thirsy pernif" is a half, and 43% "foursy three pernif" is three quarters. what I think is really cool about pernifs is how naturally they relate to probability. if you roll a cubic die, there's a 10% chance that the result will be 10. if you roll TWO cubic dice, there's exactly a 1% chance that the result will be 20. since rolling six sided dice is usually the first thing anyone learns about probability, it's really serendipitous that using seximal, all the numbers involved are 100% ("nif pernif"? that sounds kinda silly, doesn't it? oh well.) easier to deal with and think about.