A lesson about systems of counting.

1. SYSTEMS OF COUNTING
+ Binary
+ Octal
+ Decimal
+ Hexadecimal

2. Numeric Systems used in Computers
Input Output
0 = 1 Invert (NOT)
1 = 0
Inputs Output +---+
0 + 0 = 0 | 1 |
0 + 1 = 1 0R | 0 | (Not OR)
1 + 0 = 1 | 0 | NOR
1 + 1 = 1 | 0 |
+---+
Inputs Output +---+
0 x 0 = 0 | 1 |
0 x 1 = 0 AND| 1 |(Not AND)
1 x 0 = 0 | 1 |
1 x 1 = 1 | 0 |-----NAND
+---+
Inputs Output
0 + 0 = 00
0 + 1 = 01 ADD
1 + 0 = 01
1 + 1 = 10

3. Google Advanced Search
http://www.google.com/advanced_search

4. So to find pages with...
all these words:
this is an 'AND' function that requires ALL the words to be present
anywhere on the web page for a positive output.
this exact word or phrase:
this is an 'AND' function that requires ALL the words to be present
anywhere on the web page BUT NEXT TO EACH OTHER for a positive
output.
any of these words:
This is a simple 'OR' function. If any word is present anywhere
there is a positive output.
none of these words:
This is a simple 'NOT' function. A positive output will result from
NOT having the word present.
You can take a set of words as above, and look for a positive
outcome from NOT having them. Thus producing NAND and NOR outputs.

5. Numbering systems
Hexadecimal --> base16 .... 16³ 16² 16¹ 16°
Decimal --> base10 .... 10³ 10² 10¹ 10°
Octal --> base8 .... 8³ 8² 8¹ 8°
Binary --> base2 .... 2³ 2² 2¹ 2°
All these systems are used to define important
aspects of application behaviour.
This includes colour definitions in web code,
photo/paint editing, and internet communications
for example.

6. Relating the number systems
Decimal Hexadecimal Binary
10² 10¹ 10° 16¹ 16° 2³ 2² 2¹ 2°
0 0 0 0 0 0 0 0 0
0 0 1 0 1 0 0 0 1
0 0 2 0 2 0 0 1 0
0 0 3 0 3 0 0 1 1
0 0 4 0 4 0 1 0 0
0 0 5 0 5 0 1 0 1
0 0 6 0 6 0 1 1 0
0 0 7 0 7 0 1 1 1
0 0 8 0 8 1 0 0 0
0 0 9 0 9 1 0 0 1
0 1 0 0 A 1 0 1 0
0 1 1 0 B 1 0 1 1
0 1 2 0 C 1 1 0 0
0 1 3 0 D 1 1 0 1
0 1 4 0 E 1 1 1 0