1 byte may hold 1 character.
For Example:
Refer Ascii values for each character & convert into binary.
This is how it works.
value 255 is stored as (11111111) base 2.
Visit this link for knowing more about binary conversion.
http://acc6.its.brooklyn.cuny.edu/~gurwitz/core5/nav2tool.html
Size of Tiny Int = 1 Byte ( -128 to 127)
Int = 4 Bytes (-2147483648 to 2147483647)