Future Missions : near - Earth Asteroids * Lagrange points * The Moon * The Red Planet Mars * Deep Space destinations

THE ORION PROJECT
##### Exploration Flight Test 1 planned for 2014 Which will be Launched By The SLS or TheSpace Launch System In mathematics and computer sciencehexadecimal (also base 16, or hex) is a positional numeral system with a radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols 09 to represent values zero to nine, and A, B, C, D, E, F (or alternatively af) to represent values ten to fifteen. For example, the hexadecimal number 2AF3 is equal, in decimal, to (2 × 163) + (10 × 162) + (15 × 161) + (3 × 160), or 10995.

Each hexadecimal digit represents four binary digits (bits), and the primary use of hexadecimal notation is a human-friendly representation of binary-codedvalues in computing and digital electronics. One hexadecimal digit represents a nibble, which is half of an octet or byte (8 bits). For example, byte values can range from 0 to 255 (decimal), but may be more conveniently represented as two hexadecimal digits in the range 00 to FF. Hexadecimal is also commonly used to represent computer memory addresses.

Color references in HTML and CSS and X Window can be expressed with six hexadecimal digits (two each for the red, green, and blue components, in that order) prefixed with #: white, for example, is represented #FFFFFF . CSS allows 3-hexdigit abbreviations with one hexdigit per component: #FA3 abbreviates #FFAA33 (a golden orange:     ).

Simple key for notations used in article:

Full Text Notation Abbreviation Number Base
binary bin 2
octal oct 8
decimal dec 10

# Decimal And Hexadecimal

The decimal system uses a base of ten. This means that ten different symbols are used to represent the ten consecutive integers 0, 1, 2, 3, 4, 5, 6, 7, 8, 9. When you want to count past the last symbol, you start to combine symbols.

 DEC 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19

The same applies to the hexadecimal numbering system except it uses 16 symbols. These are the numbers 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 and the letters A, B, C, D, E and F. The table below shows how to combine the symbols to create bigger numbers.

 DEC HEX 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 0 1 2 3 4 5 6 7 8 9 A B C D E F 10 11 12 13 14 15 16 17 18 19 1A 1B 1C 1D 1E 1F

# Converting Hexadecimal Numbers to Decimal Numbers

Converting hexadecimal numbers to their decimal numbers isn't an essential skill for working with RGB however being able to convert an RGB color into its decimal brightness level equivalents can make it easier to understand (not everybody thinks in "hex").

When we look at a decimal number, we divide it up into columns of ones, tens, hundreds etc. Starting from the right hand side each column is equivalent to a consecutive power of the base number.