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.
Binary: The Computer's Language
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)
Practice questions for Binary & Hex
Which of the following correctly describes the hexadecimal number system?
Explain why hexadecimal is used instead of binary when programmers write memory addresses and colour codes. Give three reasons.