Key term
WJEC A-Level Computer Science 601-5345-3
Hardware: Architecture, Memory and Storage
Networks and Data Transmission
Logic Gates and Boolean Algebra
Data Representation and Data Types
Data Structures
Organisation of Data: Files and Records
Database Systems
The Operating System
Algorithms and Programs
Principles of Programming
Systems Analysis
Software Engineering and Program Construction
Topic overviewIntegrated development environments and their purposeEditors, syntax highlighting and code entry toolsDebugging tools: breakpoints, stepping and watchesTranslation, source code and object codeLexical analysis and the symbol tableSyntax and semantic analysisCode generation and optimisation
Types of Software System
Practical Programming
Data Security and Integrity
Computing, Society and the Law
Topic overviewSocial and economic change from computingComputers and the nature of employmentThe digital divide and cultural changeEnvironmental cost of computingData protection and freedom of information lawThe Computer Misuse Act 1990 and computer crimeCopyright, surveillance and professional codes
Advanced Data Structures and Logic
Recursion, Sorting and Searching
Programming Paradigms and Translators
Topic overviewFunctional, declarative and imperative paradigmsClasses, methods and object-oriented designStandardisation of computer languagesAmbiguity in natural language and unambiguous notationBackus-Naur form and syntax diagramsCompilers, interpreters and assemblersTranslation and execution errors
System Design and Human-Computer Interaction
Software Engineering Tools and Professional Practice
Topic overviewSoftware tools for the software engineering processSoftware packages in systems analysis and specificationSoftware packages in systems designTesting tools and testing strategiesProgram version managementProgram libraries and project management toolsCodes of conduct and professional behaviour
Advanced Architecture and Assembly Language
Communication Networks and File Organisation
Number Representation and Floating Point
Databases and Distributed Systems
Topic overviewConsistency, redundancy and data independenceRelational organisation and normalisationRestructuring data into third normal formEntity relationship modellingQuery languages and SQLValidation, verification and the DBMSBig Data, data warehousing and miningDistributed systems and distributed databases
Operating System Management
Software Systems and Applications
Data Security, Cryptography and Attack
Number Representation and Floating Point
Two's complement
- 3 things to know
- A2 Unit 4
Overview
Recall questions on invert-and-add-one, representing −5 and −100, reading 11111011 and 11010110, the 8-bit and 16-bit ranges, why the negative range is one larger, the negative place value of the top bit, subtraction, and sign extension.
What you need to know
Answer each one before you reveal it.
Your recallNot started
Key term
State the range of an 8-bit two's complement number.
Key term
State the range of a 16-bit two's complement number.
Questions from this subtopic
Each one with the model answer underneath.
- 1
State the method for finding the two's complement of a binary number.
Model answer
Invert every bit and then add one.
- 2
Find the 8-bit two's complement representation of −5.
Model answer
11111011.
- 3
What denary value does 11111011 hold in 8-bit two's complement?
Model answer
−5.
- 4
State the range of an 8-bit two's complement number.
Model answer
−128 to +127.
- 5
Why is the negative range one larger than the positive?
Model answer
There is only one representation of zero, so the spare pattern 10000000 is used for −128.
- 6
What is the place value of the most significant bit in 8-bit two's complement?
Model answer
−128.
Other ways to work this
The same content, four other ways.
What is inside Levo
Six ways to work the same material.
Every question in Number Representation and Floating Point, on a schedule.
Attempt a question from memory, write the correct version, then attempt it again. Levo records the jump between your first attempt and your last, and brings each question back on the day you are due to forget it.
Or £46 a year, about £3.83 a month. Cancel anytime.