Binary code is a system of representing numbers, letters, commands, images
and sounds. Amazingly, it uses only two types of information to do this – 1 and
0. The strings of 1’s and 0’s that make up binary code may seem random, but of
course they’re not.
Binary code is at the absolute heart of anything that goes on inside a computer.
Binary Numbers
The binary number system is a base-two system, meaning it uses two distinct
digits – 0 and 1. The decimal number system we’re all familiar with is a base-ten
system, meaning it uses ten distinct digits – 0 and 1, but also 2, 3, 4, 5, 6, 7, 8
and 9.
Counting in the decimal system, when all ten digits have been exhausted, the
next number is represented as ’10’. In the binary system, it’s the exact same.
After 0 and 1 comes 10. In fact, here are the first 15 numbers expressed in
binary:
0, 1, 10, 11, 100, 101, 110, 111, 1000, 1001, 1010, 1011, 1100, 1101, 1110, 1111.
As you can see, the binary system counts up in a logical order, and whenever a
number made up of entirely 1’s is reached, an extra digit is added. This is
exactly the same thing that happens in the decimal system when a number
made up of entirely 9’s is reached.
As you can also see, there are 16 distinct numbers that can be represented in 4
digits or less (1 through 15 as well as 0). This can be calculated because 16 =
2 4.
However, binary numbers in a computing context are always represented in 8
digits or less – 8 binary digits forming one byte. The total quantity of distinct
numbers that can be represented in 8 digits is 28 = 256. 1 through 255 as well
as 0.
So 255 in binary is 11111111.
Binary Letters
Binary code representing numbers is pretty uniform – there’s only one way to do
it. However, there are multiple methods of representing letters and symbols in
binary code. These methods are called encodings.
For example, the ASCII encoding assigns unique binary bytes to 128
different characters. This makes it possible to encode any string of text.
This is the string ‘Hello World’ encoded in ASCII:
01001000 01100101 01101100 01101100 01101111 00100000
01010111 01101111 01110010 01101100 01100100
Each byte represents a letter (except for the one that represents the space
between the words, of course). The spaces between the bytes are only there to
make the binary more readable for us. Computers do not read them.
Other Applications of Binary
As well as numbers and letters, binary code can represent commands, images
and sounds – but that’s beyond the scope of this tutorial. It really is amazing
how just two digits can do so much.

help = (01101000011001010110110001110000)2

sea = (011100110110010101100001)2

love = (01101100011011110111011001100101)2
Lets Practice:
Letter to
ASCII Code to
Binary
128
64
32
16
8
4
2
1
128
64
32
16
8
4
2
1
128
64
32
16
8
4
2
1
128
64
32
16
8
4
2
1