Data Representation

Binary, denary and hexadecimal, units of storage, and how text, images and sound are represented.

Computers store everything in binary — combinations of 0s and 1s.

Number systems

Binary (base 2): place values

\dots 16, 8, 4, 2, 1

Denary (base 10): the everyday system.

Hexadecimal (base 16): digits 0–9 then A–F; a compact way to write binary (one hex digit = four bits).

Worked example. Binary $1011 = 8 + 0 + 2 + 1 = 11$ in denary. Denary $25 = 16 + 8 + 1 = 11001$ in binary.

Create a free account to read this note in full. Every free account gets 2 complete revision notes — no card needed.

Number systems

Binary (base 2): place values

\dots 16, 8, 4, 2, 1

Denary (base 10): the everyday system.

Hexadecimal (base 16): digits 0–9 then A–F; a compact way to write binary (one hex digit = four bits).

Worked example. Binary

1011 = 8 + 0 + 2 + 1 = 11

in denary. Denary

25 = 16 + 8 + 1 = 11001

in binary.