Free Number systems questions for IGCSE Computer Science (0478), part of Data representation. Each question has the answer and the marking points an examiner would look for.
Generate a full Number Systems worksheet →All Data representation questionsAdd the 8-bit binary integers 10110100 and 01001111. Give your answer in 8-bit binary.
An error occurs in part (a). Identify and describe the error.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | 00000011 Working with correct carries M1 00000011 A1 | 2 |
| (b) | Overflow error: the result needs more than 8 bits, so the ninth bit is lost Overflow (error) B1 Result > 255 / needs a ninth bit that cannot be stored B1 | 2 |
The binary number 00010010 has a logical shift 2 places to the left. Give the result.
State the effect of this shift on the denary value.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | 01001000 01001000 B1 | 1 |
| (b) | multiplied by 4 × 4 B1 | 1 |
Convert the denary number 225 into 8-bit binary.
Convert the binary number 00011110 into hexadecimal.
Convert the hexadecimal number 38 into denary.
Give the 8-bit two’s complement representation of −36.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | 11100001 11100001 B1 | 1 |
| (b) | 1E 1E B1 | 1 |
| (c) | 56 56 B1 | 1 |
| (d) | 11011100 11011100 B1 | 1 |
State what is meant by the term overflow error.
State what is meant by the term hexadecimal.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | An error when a result needs more bits than are available An error when a result needs more bits than are available B1 | 1 |
| (b) | A base-16 number system using the digits 0–9 and letters A–F A base-16 number system using the digits 0–9 and letters A–F B1 | 1 |
Add the 8-bit binary integers 01001111 and 11000101. Give your answer in 8-bit binary.
An error occurs in part (a). Identify and describe the error.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | 00010100 Working with correct carries M1 00010100 A1 | 2 |
| (b) | Overflow error: the result needs more than 8 bits, so the ninth bit is lost Overflow (error) B1 Result > 255 / needs a ninth bit that cannot be stored B1 | 2 |
The binary number 00001000 has a logical shift 2 places to the left. Give the result.
State the effect of this shift on the denary value.
| Part | Answer and marking points | Marks |
|---|---|---|
| (a) | 00100000 00100000 B1 | 1 |
| (b) | multiplied by 4 × 4 B1 | 1 |
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Meet Riyaz →Original Cambridge-style practice questions written for mentorriyaz.in. These are not Cambridge past paper questions, and this site is not affiliated with or endorsed by Cambridge University Press & Assessment. Updated 2026-11-04. Paper generator · mentorriyaz.in