Binary (4-bit)

The computer language of 0s and 1s.

What is Binary?

  • Computers store and use data as a series of 0s and 1s.
  • This system is called binary because it only has two options: on or off.
  • It’s like a set of light switches: 0 means off, and 1 means on.

Why Do Computers Use Binary?

Computers use binary because they operate with electrical signals that are either on or off. These two states are represented as 1 (on) and 0 (off).

Binary and Denary

  • Denary is the number system we use every day (0–9).
  • Binary is how computers count, using only 0 and 1.

Nibbles and Bytes

  • Nibble is 4 bits (1001)
  • Byte is 8 bits (10011001)

How to Convert Between Binary and Denary

Binary to Denary (Computer to Human Numbers)

Each binary digit (0 or 1) represents a value. Think of it as switches for different amounts:

Switch Value 8 4 2 1
Binary Number 1 1 0 1

If the switch is 1, add that value:

  • In this example: 8 + 4 + 0 + 1 = 11
  • So, 1101 in binary = 13 in denary

Denary to Binary (Human Numbers to Computer)

Start with a number and turn on switches (1) for the biggest values that fit.

Example: Convert 9 to binary:

  • 9 can use the 8 switch → turn it on (1)
  • 1 is left over → turn on the 1 switch
  • Fill the rest with 0
Switch Value 8 4 2 1
Binary Number 1 0 0 1

So, 9 = 1001 in binary

Key Points

  • Computers use binary (0s and 1s) to store information
  • Binary to Denary: Add the values for switches turned on
  • Denary to Binary: Turn on switches (1) starting with the biggest values that fit

Targets

Describe why computers use binary

State that computers store data using binary (0s and 1s)

Convert denary into 4-bit binary

Convert 4-bit binary into denary