Editing Vigesimal (section)

== Places ==
In a vigesimal [[Numerical digit|place]] system, twenty individual numerals (or digit symbols) are used, ten more than in the decimal system. One modern method of finding the extra needed symbols is to write [[10 (number)|ten]] as the letter A, or {{vigesimal|10}} , where the <sub>20</sub> means [[radix|base]] {{num|20}}, to write [[19 (number)|nineteen]] as {{vigesimal|19}}, and the numbers between with the corresponding letters of the alphabet. This is similar to the common [[Computer science|computer-science]] practice of writing [[hexadecimal]] numerals over 9 with the letters "A–F". Another less common method skips over the letter "I", in order to avoid confusion between I<sub>20</sub> as [[18 (number)|eighteen]] and [[1 (number)|one]], so that the number eighteen is written as J<sub>20</sub>, and nineteen is written as K<sub>20</sub>. The number twenty is written as {{vigesimal|20}}.

{|
|valign=top|
{|class="wikitable" style="text-align:center;"
|+Comparison
!Decimal!!colspan="2"|Vigesimal||Name spelled out<br>(in English)
|-
|0||colspan="2"|0||zero
|-
|1||colspan="2"|1||one
|-
|2||colspan="2"|2||two
|-
|3||colspan="2"|3||three
|-
|4||colspan="2"|4||four
|-
|5||colspan="2"|5||five
|-
|6||colspan="2"|6||six
|-
|7||colspan="2"|7||seven
|-
|8||colspan="2"|8||eight
|-
|9||colspan="2"|9||nine
|-
|10||colspan="2"|A||ten
|-
|11||colspan="2"|B||eleven
|-
|12||colspan="2"|C||twelve
|-
|13||colspan="2"|D||thirteen
|-
|14||colspan="2"|E||fourteen
|-
|15||colspan="2"|F||fifteen
|-
|16||colspan="2"|G||sixteen
|-
|17||colspan="2"|H||seventeen
|-
|18||I||J||eighteen
|-
|19||J||K||nineteen
|-
|20||colspan="2"|10||twenty
|-
|400||colspan="2"|100||four hundred
|-
|8000||colspan="2"|1000||eight thousand
|-
|160000||colspan="2"|10000||one hundred and<br>sixty thousand
|}
|width=35|
|valign=top|

{| class="wikitable" style="text-align:center;"
|+ Vigesimal [[multiplication table]]
|-
! 1 || 2 || 3|| 4 || 5 || 6 || 7 || 8 || 9 || A || B || C || D || E || F || G || H || I || J || 10
|-
! 2
| 4 || 6 || 8 || A || C || E || G || I || 10 || 12 || 14 || 16 || 18 || 1A || 1C || 1E || 1G || 1I || 20
|-
! 3
| 6 || 9 || C || F || I || 11 || 14 || 17 || 1A || 1D || 1G || 1J || 22 || 25 || 28 || 2B || 2E || 2H || 30
|-
! 4
| 8 || C || G || 10 || 14 || 18 || 1C || 1G || 20 || 24 || 28 || 2C || 2G || 30 || 34 || 38 || 3C || 3G || 40
|-
! 5
| A || F || 10 || 15 || 1A || 1F || 20 || 25 || 2A || 2F || 30 || 35 || 3A || 3F || 40 || 45 || 4A || 4F || 50
|-
! 6
| C || I || 14 || 1A || 1G || 22 || 28 || 2E || 30 || 36 || 3C || 3I || 44 || 4A || 4G || 52 || 58 || 5E || 60
|-
! 7
| E || 11 || 18 || 1F || 22 || 29 || 2G || 33 || 3A || 3H || 44 || 4B || 4I || 55 || 5C || 5J || 66 || 6D || 70
|-
! 8
| G || 14 || 1C || 20 || 28 || 2G || 34 || 3C || 40 || 48 || 4G || 54 || 5C || 60 || 68 || 6G || 74 || 7C || 80
|-
! 9
| I || 17 || 1G || 25 || 2E || 33 || 3C || 41 || 4A || 4J || 58 || 5H || 66 || 6F || 74 || 7D || 82 || 8B || 90
|-
! A
| 10 || 1A || 20 || 2A || 30 || 3A || 40 || 4A || 50 || 5A || 60 || 6A || 70 || 7A || 80 || 8A || 90 || 9A || A0
|-
! B
| 12 || 1D || 24 || 2F || 36 || 3H || 48 || 4J || 5A || 61 || 6C || 73 || 7E || 85 || 8G || 97 || 9I || A9 || B0
|-
! C
| 14 || 1G || 28 || 30 || 3C || 44 || 4G || 58 || 60 || 6C || 74 || 7G || 88 || 90 || 9C || A4 || AG || B8 || C0
|-
! D
| 16 || 1J || 2C || 35 || 3I || 4B || 54 || 5H || 6A || 73 || 7G || 89 || 92 || 9F || A8 || B1 || BE || C7 || D0
|-
! E
| 18 || 22 || 2G || 3A || 44 || 4I || 5C || 66 || 70 || 7E || 88 || 92 || 9G || AA || B4 || BI || CC || D6 || E0
|-
! F
| 1A || 25 || 30 || 3F || 4A || 55 || 60 || 6F || 7A || 85 || 90 || 9F || AA || B5 || C0 || CF || DA || E5 || F0
|-
! G
| 1C || 28 || 34 || 40 || 4G || 5C || 68 || 74 || 80 || 8G || 9C || A8 || B4 || C0 || CG || DC || E8 || F4 || G0
|-
! H
| 1E || 2B || 38 || 45 || 52 || 5J || 6G || 7D || 8A || 97 || A4 || B1 || BI || CF || DC || E9 || F6 || G3 || H0
|-
! I
| 1G || 2E || 3C || 4A || 58 || 66 || 74 || 82 || 90 || 9I || AG || BE || CC || DA || E8 || F6 || G4 || H2 || I0
|-
! J
| 1I || 2H || 3G || 4F || 5E || 6D || 7C || 8B || 9A || A9 || B8 || C7 || D6 || E5 || F4 || G3 || H2 || I1 || J0
|-
! 10
| 20 || 30 || 40 || 50 || 60 || 70 || 80 || 90 || A0 || B0 || C0 || D0 || E0|| F0 || G0 || H0 || I0 || J0 || 100
|}
|}
According to this notation:
:{{vigesimal|40}} is equivalent to [[40 (number)|forty]] in decimal = {{nowrap|(2 × 20<sup>1</sup>) + (0 × 20<sup>0</sup>)}}
:{{vigesimal|260}} is equivalent to [[260 (number)|two hundred and sixty]] in decimal = {{nowrap|(13 × 20<sup>1</sup>) + (0 × 20<sup>0</sup>)}}
:{{vigesimal|400}} is equivalent to [[400 (number)|four hundred]] in decimal = {{nowrap|(1 × 20<sup>2</sup>) + (0 × 20<sup>1</sup>) + (0 × 20<sup>0</sup>)}}.

In the rest of this article below, numbers are expressed in decimal notation, unless specified otherwise. For example, '''10''' means [[10 (number)|ten]], '''20''' means [[20 (number)|twenty]]. Numbers in vigesimal notation use the convention that I means eighteen and J means nineteen.