Binary to Denary Conversion

Part of Binary & Hex · Section 7 of 15

Key FactsUnit: 3.3 Data RepresentationGCSE

This key facts covers Binary to Denary Conversion 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 7 of 15 in this topic. Use this key facts to connect the idea to the wider topic before moving on to questions and flashcards.

Binary to Denary Conversion

Method: Add up place values where there's a 1

Example 1: Convert 11010110 to denary

  Place values: 128  64  32  16   8   4   2   1
  Binary:         1   1   0   1   0   1   1   0
  
  Add where there's a 1:
  128 + 64 + 16 + 4 + 2 = 214 (denary)
  

Example 2: Convert 10101 to denary

  Place values: 16   8   4   2   1
  Binary:        1   0   1   0   1
  
  16 + 4 + 1 = 21 (denary)
  

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

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