Grade 1218 periods
Data Representation
Investigates how instructions and data are represented in computers and exploit them in arithmetic and logic operations
Exam objectives
- Convert between decimal, binary, octal and hexadecimal in both directions
- Represent signed integers using signed-magnitude, one's complement and two's complement
- Explain the role of the MSB as a sign bit and why two's complement is preferred for arithmetic
Important areas to cover
- Number-system conversion and complement questions are near-guaranteed every year — in MCQ as quick conversions and in Paper II Part A as multi-step problems
- Two's complement is the single most consistently examined numeric skill in this unit — drill it until automatic
Lesson content not added yet.
Exam objectives
- List character-encoding schemes: BCD, EBCDIC, ASCII, Unicode
- Convert a given symbol or string into a stated encoding scheme
- State an advantage/disadvantage of each scheme (e.g. ASCII's limited range vs Unicode's multilingual support)
Important areas to cover
- "Why is Unicode needed for Sinhala/Tamil text" is a common local-context question
Lesson content not added yet.
Exam objectives
- Add and subtract multi-digit binary integers, with carry/borrow shown
- Perform bitwise NOT, AND, OR and XOR operations on binary numbers
Important areas to cover
- Binary addition/subtraction with full working shown is a reliable Paper II Part A question
- Bitwise-operation MCQs (evaluate the result) are common
Lesson content not added yet.