Explain how binary is used to store data

• Binary uses only two digits: 0 and 1.
• These digits are bits. A group of 8 bits = a byte.
• Binary suits computers because electronic components reliably represent two states:
  • off/on
  • low/high voltage
  • false/true
• Each bit has a place value based on powers of 2.

Bit position	7	6	5	4	3	2	1	0
Value	128	64	32	16	8	4	2	1

Binary can store:

• numbers as binary place values
• text as character codes (ASCII, Unicode)
• images as binary colour values per pixel
• audio as binary sample values
• instructions as binary machine code

Number of values

• With n bits → 2^n combinations.
  • 3 bits → 2^3 = 8 values.
  • 8 bits → 2^8 = 256 values.

Unsigned vs Signed binary

• Unsigned: only non-negative values. 8 bits → 0 to 255.
• Signed: positive and negative values; often uses two’s complement. 8 bits → -128 to 127.