Rihan uses a decimal (base ten) system just as does English. Numbers above ten are formed by combining the nearest ten with the base digit, e.g. dha'hwi, "eleven," is literally "ten'one."

Numbers above 100 are formed similarly, e.g. khu-dha'hwi, "111", is literally "100-ten'one."

Thousands is expressed by the word dhei. It, however, is used differently in Rihan than it is in English. Dhei means "a group of three zeroes." Thus, hwi dhei, "1,000," literally means "1 followed by a group of three zeroes." Similarly, lha'sei dhei, "93,000," literally means "93 followed by a group of three zeroes."

The concept of dhei becomes more complicated to English speakers in numbers above a "million." As dhei represents "a group of three zeroes," kre-dhei refers to "two groups of zeroes," or "six zeroes," thus kre-dhei is how one would say "million" in Rihan. Similarly, sei-dhei, "three groups of zeroes" is a "billion," and mnhe-dhei, "four groups of zeroes" is a "trillion."

Fractions are formed with the particle erh', with the denominator first, for example seha erh'lli means "seven thirtieths."

The decimal point is represented by the word errah, with numbers after the decimal point pronounced separately. "3.1415" would be rendered as sei errah hwi mne hwi rhi.

Numbers in Rihan should be spelled out in formal writing unless used in mathematics or scientific notations. In common writing, the symbols for a number may be used. Rihan uses a shorthand notation system for ordinal numbers that is similar to English. Ordinal numbers in this system are written nuXr, e.g. nu3r, "third."

Numbers in Rihan
Cardinal Numbers Ordinal Numbers Adverbial Numbers
0 lliu - - - -
1 hwi 1st nuhwir, ih'hwi once joaie
2 kre 2nd nukrer twice caehh'kre
3 sei 3rd nuseir 3 times caehh'sei
4 mne 4th numner 4 times caehh'mne
5 rhi 5th nurhir 5 times caehh'rhi
6 fve 6th nufver 6 times caehh'fve
7 lli 7th nullir 7 times caehh'lli
8 the 8th nuther 8 times caehh'the
9 lhi 8th nulhir 9 times caehh'lhi
10 dha 10th nudhar 10 times caehh'dha
11 dha'hwi 11th nudha'hwir 11 times caehh'dha'hwi
12 dha'kre 12th nudha'krer 12 times caehh'dha'kre
20 kra 20th nukrar 20 times caehh'kra
30 seha 30th nusehar 30 times caehh'seha
40 mnha 40th numnhar 40 times caehh'mnha
50 rha 50th nurhar 50 times caehh'rha
60 fvha 60th nufvhar 60 times caehh'fvha
70 lla 70th nullar 70 times caehh'lla
80 thha 80th nuthhar 80 times caehh'thha
90 lha 90th nulhar 90 times caehh'lha
100 khu 100th nukhur 100 times caehh'khu
101 khu-hwi 101th nukhu-hwir 101 times caehh'khu-hwir
110 khu-dha 110th nukhu-dha 110 times caehh'khu-dha
111 khu-dha'hwi 111th nukhu-dha'hwir 111 times caehh'khu-dha'hwir
200 kru 200th nukrur 200 times caehh'kru
300 sehu 300th nusehur 300 times caehh'sehu
400 mnhu 400th numnhur 400 times caehh'mnhu
500 rhu 500th nurhur 500 times caehh'rhu
600 fvhu 600th nufvhur 600 times caehh'fvhu
700 llu 700th nullur 700 times caehh'llu
800 thhu 800th nuthhur 800 times caehh'thhu
900 lhu 900th nulhur 900 times caehh'lhu
1,000 hwi dhei 1,000th nuhwi'dheir 1,000 times caehh'hwi'dhei
2,000 kre dhei 2,000th nukre'dheir 2,000 times caehh'kre'dhei
2,111 kre dhei khu-dha'hwi 2,111th nukre'dhei'khu-dha'hwir 2,111 times caehh'kre'dhei'khu-dha'hwi
43,000 mnha'sei dhei 43,000th numnha'sei'dheir 43,000 times caehh'mnha'sei'dhei
365,000 sehu-fvha'rhi dhei 365,000th nusehu-fvha'rhi'dheir 365,000 times caehh'sehu-fvha'rhi'dhei
1 million hwi kre-dhei millionth nuhwi'kre-dheir a million times caehh'hwi'kre-dhei
2 million kre kre-dhei 2-millionth nukre'kre-dheir 2 million times caehh'kre'kre-dhei
43 million mnha'sei kre-dhei 43-millionth numnha'sei'kre-dheir 43 mil. times caehh'mnha'sei'kre-dhei
1 billion hwi sei-dhei a billionth nuhwi'sei-dheir billion times caehh'hwi'sei-dhei
1 trillion hwi mnhe-dhei a trillionth nuhwi'mnhe-dheir trillion times caehh'hwi'mnhe-dhei