Understanding Place Values in Binary:

Just like denary has place values (ones, tens, hundreds), binary has place values based on powers of 2:

  Bit Position:  7      6     5    4    3   2   1   0
  Place Value:   128    64    32   16   8   4   2   1
  
  Example: 10110101
           1×128 + 0×64 + 1×32 + 1×16 + 0×8 + 1×4 + 0×2 + 1×1
           = 128 + 32 + 16 + 4 + 1 = 181 (denary)

Key Concepts:

Bit: A single binary digit (0 or 1)
8-bit binary: Can represent 0-255 (2⁸ = 256 values)
16-bit binary: Can represent 0-65,535 (2¹⁶ = 65,536 values)
Most Significant Bit (MSB): Leftmost bit (highest value)
Least Significant Bit (LSB): Rightmost bit (lowest value)

This key facts covers Binary: The Computer's Language within Binary & Hex for GCSE Computer Science. Revise Binary & Hex in 3.3 Data Representation for GCSE Computer Science with 16 exam-style questions and 22 flashcards. This is a high-frequency topic, so it is worth revising until the explanation feels precise and repeatable. It is section 5 of 15 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.

Practice questions for Binary & Hex

Which of the following correctly describes the hexadecimal number system?

A. Base 2, using digits 0 and 1
B. Base 8, using digits 0 to 7
C. Base 16, using digits 0-9 and letters A-F
D. Base 16, using digits 0-9 and letters A-G

1 markfoundation

Explain why hexadecimal is used instead of binary when programmers write memory addresses and colour codes. Give three reasons.

3 marksstandard

Binary: The Computer's Language

Practice questions for Binary & Hex

Quick recall flashcards

16 questions on Binary & Hex: practise free