4-Bit Binary

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.

Binary and Denary

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

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

You should be able to explain what binary is

You should be able to convert binary to denary

You should be able to convert denary to binary