Binary is a numeric system which uses two numerals to represent all real numbers. While the most common counting system, the decimal system, uses ten numerals, binary uses only 0 and 1.
Each digit in a binary number system therefore represents a power of two. The first digit on the right represents the 0th power, the second represents the 1st power, the third represents the 2nd power, and so on. So the number 1 in the decimal system is represented also as 1 in the binary system. The number 23, by contrast, is represented as 10111 (16+0+4+2+1).
The decimal system makes perfect sense for human beings to use. We have ten fingers and ten toes, so when early humans began counting things they turned to these readily available markers. Later, when systems of counting became codified, it was natural to convert the already used decimal system to a representational system. Binary is also a fairly natural system, however, since many things either "are" or "are not." Many spiritualist traditions, such as the Pythagoreans and some Indian mystics, therefore made use of this system, beginning in the 6th century BC.
In 1854, a central paper on binary systems was published by the mathematician George Boole. This paper laid out the groundwork for what would eventually be called Boolean algebra. With the advent of electronics, these systems suddenly made incredible sense. Most electronic systems function on a switchbased system, with current either running or not running. In 1937, Claude Shannon set out the foundations for the theory of circuit design using binary arithmetic. In 1940, the age of binary computing began with the release of Bell Labs Complex Number Computer, which was able to perform extremely complex mathematical calculations using this type of system.
In a more general sense, binary systems can be anything which offers only two options, not necessarily limited to numerical systems. In the case of electronic switches, for example, the system consists of currentno current. A truefalse exam is another example. Yesno questions are also binary in nature.
Mathematical methods exist for transforming binary numbers into decimal numbers, and visaversa. There are also mathematical devices for performing functions such as addition, subtraction, multiplication and division in different basesystems, including binary. While conversion to or from decimal is somewhat labored, converting between binary and octal or hexadecimal systems, baseeight and base16 respectively, is much easier. This is because both eight and 16 are powers of two, making them integrate well with binary systems. It is for this reason that both octal and hexadecimal are widely used basesystems in computer applications.
anon357630 Post 27 
Whoever invented this system was really clever! 
anon305401 Post 24 
101010100000  like that? 
anon297037 Post 23 
This is fascinating! My brother keeps talking about this, asking if I've learned it yet, and because I love him I looked it up. He'll be surprised! 
anon163598 Post 20 
could you please include when you posted this articlemonth, day, year? It'll help for citing purposes. Thanks! Moderator's reply: Thanks for visiting wiseGEEK! We post all of the applicable information we can provide on each article page  that doesn’t include the published date or sources. Generally, the accessed date works for bibliographies calling for a date. You’ll find the author's name below the article, centerjustified.

anon114035 Post 18 
Binary Code is most commonly used in BIOS(Basic Input Output System).Which is used in computers Binary numbers (1 or 0) represent on(1) or off(0). Typically you work out binary like this: 256 128 64 32 16 8 4 2 1 If you have say a decimal number of 254, to work out the binary code you would use the system above to work it out. So, 256 128 64 32 16 8 4 2 1 0 1 1 1 1 1 1 1 0 The number that was given (254) is equated in the system above if you were to add up the numbers that have 1s underneath them.From there you can learn to translate binary into decimal, decimal
into hexidecimal (not using binary,because hex is a whole other language base) which then goes onto C++ programming and all the rest.
If you're working out bigger numbers, for instance 3813, then you need to create a bigger system in order to work out the binary code so therefore you need to do this: 2048 1024 512 256 128 64 32 16 8 4 2 1 1 1 1 0 1 1 1 0 0 1 0 1 So this is your Binary Code for 3813: 1 1 1 0 1 1 1 0 0 1 0 1 If you want to be lazy you can just use your calculator on your computer. You need to switch the view to scientific which calculates binary, decimal, hex and octal. I suggest you make sure you understand binary code first before moving onto hex because the development between them can become very confusing. I hope this makes sense. 
anon90397 Post 17 
A "Binary Number" is a number from a base2 counting system. Humans count in base10. Several of the posts show how to convert binary numbers (up to eight columns in length) to a base10 number. To count in binary means you only have two numbers, 0 and 1! Starting from zero and counting up to seven would look like this: 0, 1, 10, 11, 100, 101, 110, 111. This allows you to keep track of eight things, don't forget about zero. 
anon67339 Post 15 
from left to right first zero = 128 second zero = 64 third zero = 32 fourth zero = 16 fifth zero = 8 sixth zero = 4 seventh zero = 2 eighth zero = 1 00000001  1 WHY? (128*0)+(64*0)+(34*0)+(16*0)+(8*0)+(4*0)+(2*0)+(1*1) = 1 00000010  2 00000011  3 00000100  4 00000101  5 ... 00010100 = 20 (128*0)+(64*0)+(32*0)+(16*1)+(8*0)+(4*1)+(2*0)+(1*0)= 0+0+0+16+0+4+0+0 = 20 sorry if there are any typos. i did it quickly. 
anon65105 Post 13 
binary: 10100 = 20? solution: 256 128 64 32 16 8 4 2 1 0 0 0 0 1 0 1 0 0 so; 16+4 = 20

anon49445 Post 12 
think of it in columns, just like the numbers you use every day. the number  1,234 right? the four represents 4 of ones. the three represents 3 of tens. the two represents 2 of one hundreds. the one represents 1 of one thousand. you understand that the number 1,000 is actually just a representation of one thousand of a single number 1. binary is the same, but with different columns. instead of ones, tens, hundres, thousands, hundredthousands, millions... you have ones, twos, fours, eights, sixy fours, etc. get it? 
anon49293 Post 11 
This wasn't very useful at all. it just sounds like abunch of numbers representing other numbers. 
anon43875 Post 9 
@8 Yes, that is correct. the far right column denotes you 2^0 which, if there is a 1 there, 2^0 equals 1, the second place is 2^1 which, following this pattern equals 2 so from 1 to 10: 1; 10; 11; 100; 101; 110; 111; 1000; 1001; 1010.

anon43411 Post 8 
So, let me get this straight (Hopefully) 10100 = 20? If not. Why not? 
anon42335 Post 7 
I still do not understand this code. O.o 
Jahpanah Post 6 
Hi According to your query a binary means on or off state for any data used digital world. 
anon17819 Post 4 
Well  After all the work I completed... it seems that absolutely no one wants the truth... So, I ask all of you, which includes the Editorial Staff: 'What is the definition of a Binary Number?' Because I concluded that the definition of a Binary Number, must be defined as; A Binary Number is the Exponent in a Base 2 Exponential Operation. 
rjohnson Post 1 
Typically in binary systems that need to indicate something is either yes/no or true/false, 0 is used for "no" or "false," and 1 is used for "yes" or "true." 