Level:
Correct: 0
Incorrect: 0
Marks: 0/0
Exam Practice
Subject:
Topics:
Cambridge IGCSE Computer Science (Paper 1) Smart practice A mixed round aimed at your weak spots
Unit 1
Data representation
Number systems
Binary, denary and hexadecimal conversions
0%
Uses of hexadecimal
0%
Binary addition and overflow
0%
Logical binary shifts
0%
Two's complement
0%
Text, sound and images
Character sets: ASCII and Unicode
0%
Representing sound
0%
Representing images
0%
Data storage and compression
Data storage units and file size calculations
0%
Data compression
0%
Unit 2
Data transmission
Types and methods of data transmission
Packets and packet switching
0%
Methods of data transmission
0%
The USB interface
0%
Methods of error detection
Parity, checksum and echo check
0%
Check digits and ARQ
0%
Encryption
Encryption
0%
Unit 3
Hardware
Computer architecture
The CPU, Von Neumann architecture and the FDE cycle
0%
Cores, cache and clock speed
0%
Instruction sets and embedded systems
0%
Input and output devices
Input devices
0%
Output devices
0%
Sensors
0%
Data storage
Primary storage: RAM and ROM
0%
Secondary storage: magnetic, optical and solid-state
0%
Virtual memory and cloud storage
0%
Network hardware
Network hardware: NIC, MAC and IP addresses, routers
0%
Unit 4
Software
Types of software and interrupts
System software, application software and operating systems
0%
Firmware and interrupts
0%
Programming languages, translators and IDEs
High-level languages, low-level languages and assembly language
0%
Compilers and interpreters
0%
Integrated development environments (IDEs)
0%
Unit 5
The internet and its uses
The internet and the world wide web
The internet, the world wide web, URLs and HTTP(S)
0%
Web browsers, locating web pages and cookies
0%
Digital currency
Digital currency and blockchain
0%
Cyber security
Cyber security threats
0%
Keeping data safe: security solutions
0%
Unit 6
Automated and emerging technologies
Automated systems
Automated systems
0%
Robotics
Robotics
0%
Artificial intelligence
Artificial intelligence
0%
Avg
score:
–
Topics
done:
0/39

Binary, denary and hexadecimal conversions

Practise 36 exam-style questions on Binary, denary and hexadecimal conversions for Cambridge IGCSE Computer Science (Paper 1). Write your answer as you would in the exam and get it marked in seconds against the mark scheme, point by point, with an AI tutor on hand if you get stuck.

  • 36 questions
  • 1–6 marks each
  • Instant marking
  • No sign-up needed
20 questions, marked as you go

Sample questions with model answers

Here are 4 of the questions in this topic, each with a model answer, an explanation of why it earns the marks and the mark scheme an examiner would use.

Question 1

1 mark

Convert the hexadecimal number 2F into denary.

Model answer

2 × 16 + 15 × 1 = 32 + 15 = 47

Explanation

The left digit is worth 16s and the right digit 1s. F stands for 15, so 2F = 32 + 15 = 47.

Mark scheme
  1. 1 mark

    47

Question 2

2 marks

Convert the denary number 200 into hexadecimal.

Show your working.

Model answer

200 ÷ 16 = 12 remainder 8
12 = C
So 200 = C8

Explanation

12 sixteens make 192 and 8 is left over, so the digits are 12 and 8. The 12 must be written as C. An alternative is to convert to binary first (1100 1000) and turn each nibble into one hexadecimal digit.

Mark scheme
  1. 1 mark

    Working, e.g. 200 ÷ 16 = 12 remainder 8 or 200 = 1100 1000 in binary

  2. 1 mark

    C8

    accept lower case (c8)

Question 3

3 marks

A microcontroller in a weather station stores a 12-bit reading. A technician's screen shows the reading as the hexadecimal number 3B7.

Convert 3B7 into 12-bit binary.

Model answer

3 = 0011
B = 11 = 1011
7 = 0111
3B7 = 0011 1011 0111

Explanation

Three hexadecimal digits give three nibbles, which is 12 bits. Convert each digit using place values 8, 4, 2, 1 and keep the leading zeros so that every nibble has four bits.

Mark scheme
  1. 1 mark

    0011 (for 3)

    one mark for each correct nibble in the correct position; accept with or without spaces; correct answer with no working scores full marks

  2. 1 mark

    1011 (for B)

  3. 1 mark

    0111 (for 7)

    final answer 0011 1011 0111

Question 4

4 marks

Four values are written in different number systems.

P: binary 1001 1010
Q: hexadecimal 9C
R: denary 155
S: hexadecimal 97

Convert P, Q and S into denary. Then write the letters P, Q, R and S in order from smallest to largest.

Model answer

P: 128 + 16 + 8 + 2 = 154
Q: 9 × 16 + 12 = 144 + 12 = 156
S: 9 × 16 + 7 = 144 + 7 = 151
Order from smallest to largest: S (151), P (154), R (155), Q (156)

Explanation

Values in different bases can only be compared once they are all in the same base, and denary is the easiest. All four values are close together, so each conversion must be exact - an error of one or two changes the order.

Mark scheme
  1. 1 mark

    P = 154

    correct answer with no working scores full marks

  2. 1 mark

    Q = 156

  3. 1 mark

    S = 151

  4. 1 mark

    Order: S, P, R, Q

    allow follow-through from incorrect conversions

Ready to try the rest? Every answer you write is marked against the mark scheme, so you can see exactly where the marks are.

AI Tutor Hints first, answers after you try

Hi! Stuck? Ask me for a hint and I’ll help you work it out. Once you’ve checked your answer I can explain exactly where the marks are.