Number Systems with Bases other than 10

 

Counting in Different Bases

Decimal (10)

Binary (2)

Octal (8)

Hex (16)

0

0

0

0

1

1

1

1

2

10

2

2

3

11

3

3

4

100

4

4

5

101

5

5

6

110

6

6

7

111

7

7

8

1000

10

8

9

1001

11

9

10

1010

12

A

11

1011

13

B

12

1100

14

C

13

1101

15

D

14

1110

16

E

15

1111

17

F

16

10000

20

10

17

10001

21

11

18

10010

22

12

19

10011

23

13

20

10100

24

14

 

Binary | Octal | Hexadecimal

 

Using different numbers bases "fell out" of the mathematics curriculum for a period of time as people felt that the base 10 was the only base used in everyday life. However, with the prevalence of technology and computers, being able to move easily in computations from one base system to another is almost as similar as in moving easily from speaking in one language to another.

We will focus on the three number bases used by computers: the binary, the octal, and hexadecimal, for: "Three numeration systems, binary, octal and hexadecimal, are used when dealing with the internal workings of computers. To be a knowledgeable, efficient programmer requires at least a rudimentary understanding of how they work and how they are interrelated."

Numeration Systems with tables
for binary, octal, and hexadecimal systems
http://www.macdonald.egate.net/CompSci/Pascal/hnumeration.html  

 

Binary or Base 2

The binary number base uses only 2 symbols: 0 and 1. The numbers are then:

Binary Number

Decimal Number

A base 2 number would be written in expanded form as:

Or converting the above number to decimal would be:

8 + 0 + 0 + 0 = 8

To add two binary numbers, the following chart is true:

Binary Addition

+

0

1

0

0

1

1

1

10

So, the two possibilities are:

A ) OR

B)

which means:

each time "carrying" over the "1."

1

1

10

2

11

3

100

4

101

5

110

6

111

7

1000

8

1001

9

1010

10

1011

11

1100

12

1101

13

1110

14

1111

15

10000

16

10001

17

10010

18

10011

19

10100

20

 

Octal or Base 8

The octal number base uses only 8 symbols: 0, 1, 2, 3, 4, 5, 6, and 7. The numbers are then:

Octal Number

Decimal Number

A base 8 number would be written in expanded form as:

which would convert to decimal form as:

16 + 1 = 17

The octal addition chart is:

+

0

1

2

3

4

5

6

7

------------------------------------------------------------------

0

|
|
|
|
|
|
|
|
|
|

0

1

2

3

4

5

6

7

1

1

2

3

4

5

6

7

10

2

2

3

4

5

6

7

10

11

3

3

4

5

6

7

10

11

12

4

4

5

6

7

10

11

12

13

5

5

6

7

10

11

12

13

14

6

6

7

10

11

12

13

14

15

7

7

10

11

12

13

14

15

16

Using the above table:

Check if your calculator offers the option of different bases. If it does not, then you can always use the calculator at:
Converting binary to octal to hexadecimal numbers http://www.terra.cc.oh.us/dlm270/session1.htm

1

1

2

2

3

3

4

4

5

5

6

6

7

7

10

8

11

9

12

10

13

11

14

12

15

13

16

14

17

15

20

16

21

17

22

18

23

19

24

20

Hexadecimal or Base 16

The hexadecimal number base uses 16 symbols. Since the decimal system only has 10 symbols,
6 more must be added. Those six are taken from the first letters of the alphabet,
so the symbols are: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, and F. The numbers are then:

Hexadecimal Number

Decimal Number

 

 

A base 16 number would be written in expanded form as:

21 = (2 x 16) + ( 1 + 1)

which would convert to decimal from as:

32 + 1 = 33

 

The hexadecimal system is most often seen
in designing web pages, where all color
combinations are represented
by hexadecimal numbers.
There are 216 cross platform colors
where each RGB color (red, green blue) is
expressed in a two digit code.

For this page,
the background has color code ="FFFFFF"
which is white. Thus, this code is broken
in three position codes, since each color ranges
from 0 - 255. So white is made up of FF for red,
FF for green, and FF for blue.
FF = 255 which is the maximum amount of color
possible.

The links on this page have color code 003366.
What would that color be?

i. e. how much red?
how much green?
how much blue?

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

10

16

11

17

12

18

13

19

14

20

  Week 3