Vigesimal

Vigesimal (also known as base 20) is a numeral system that uses 10 numbers and 10 letters (20 digits) : 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, F, G, H, I, J and sometimes K. Vigesimal is related to Kaktovik numerals system, because they both use base 20. Sometimes, they do not use I because I looks like a 1. Examples are 3F is 75 (3 x 20 + 15 = 75) in decimal or 8H is 177 (8 x 20 + 17 = 177) in decimal. If you reach J or K, you put a 1 in front and 0 on everything else. Vigesimal is nearly double of decimal because 40 in vigesimal is 80 in decimal and this only works if the number is between 10-90 (only if they end with 0).

Numbers from Vigesimal to Decimal
Left is Vigesimal, Right is Decimal
Also the letter I is in here

0 = 0

1 = 1

2 = 2

3 = 3

4 = 4

5 = 5

6 = 6

7 = 7

8 = 8

9 = 9

A = 10

B = 11

C = 12

D = 13

E = 14

F = 15

G = 16

H = 17

I = 18

J = 19

10 = 20

Arithmetic signs
In vigesimal, they may use arithmetic signs to add, subtract, multiply or divide.

Addition
For addition, if you want to add 2 vigesimal numbers you do like this:

45 + 8C = CH (Vigesimal)

85 + 172 = 257 (Decimal)

Subtraction
For subtraction, if you want to subtract 2 vigesimal numbers you do like this:

DH - 8B = 56 (Vigesimal)

277 - 171 = 106 (Decimal)

Multiplication
And for short multiplication, if you want to multiply 2 vigesimal numbers you do like this:

1F x 6 = AA (Vigesimal)

35 x 6 = 210 (Decimal)

For long multiplication, you do like this:

5A2 x C7 = 37,JEE (Vigesimal)

2,202 x 247 = 543,894 (Decimal)

Division
And for short division, if you want to divide 2 vigesimal numbers you do like this:

5A / 12 = 5 (Vigesimal)

110 / 22 = 5 (Decimal)

For long division, you do like this:

6BG / 1CJ = 4 (Vigesimal)

2636 / 659 = 4 (Decimal)

Related pages
Decimal (Base 10)
Maya numerals (A counting system uses Base 20)

References

Category:Numbering systems