1. Revision tip: Focus on the things you find difficult first.
Data representation
Revision tip: Focus on the things you find difficult first.

2. “Every lesson counts – don’t waste a minute.”
Task
Time (minutes) a
1. Complete self assessment sheet. 2
2. Read through the chapter on data representation. 15
3. Work through the questions on the revision
template focusing on weaker areas first. 25
4. Attempt the multiple choice test on Edmodo. 10
5. Attempt the past paper exam questions. 20
6. Mark past paper exam paper questions.
7. Read through the chapter on data representation.
8. Attempt the multiple choice test on Edmodo again.
“Every lesson counts – don’t waste a minute.”

3. Binary numbers (base 2)
Exam tip: When converting binary numbers in the exam, draw a
table to show your workings.
Convert to denary (base 10)
(1 mark)
Convert to denary (base 10)
(1 mark)
How many gigabytes are there in 3 terabytes?
(1 mark)
……………………………………………………
Convert to denary (base 10)
(1 mark)
How many kilobytes are there in 2.5 megabytes?
(1 mark)
……………………………………………………
Convert to denary (base 10)
(1 mark)

4. Denary (base 10) to binary (base 2)
26 (base 10) as a binary number (base 2)
Convert 115 (base 10) to binary (base 2). Show your workings.
(1 mark)
Convert 99 (base 10) to binary (base 2). Show your workings.
(1 mark)
Convert 34 (base 10) to binary (base 2). Show your workings.
(1 mark)
Convert 76 (base 10) to binary (base 2). Show your workings.
(1 mark)

5. Adding binary numbers Add 101111 and 10011 in binary. (2 marks)

6. Hexadecimal numbers Convert the hexadecimal number 5E to denary.
(2 marks)
Convert the denary number 91 to hexadecimal. (2 marks)
Convert the denary number 169 to hexadecimal. (2 marks)
Convert the hexadecimal number 3A to denary.
(2 marks)
Convert the denary number 51 to hexadecimal. (2 marks)
Convert the hexadecimal number AD to denary.
(2 marks)

7. Binary to Hex & back again
Convert to hexadecimal.
(2 marks)
Convert A5 to binary.
(2 marks)
Convert to hexadecimal.
(2 marks)
Convert 7D to binary.
(2 marks)
Convert to hexadecimal.
(2 marks)
Convert F3 to binary.
(2 marks)

8. Characters
What happens if you sort the list ‘Gorilla’, ‘bear’, ‘Elephant’, ‘Cat’, ‘dog’ in a computer program using ASCII or Unicode to represent the character set.
(2 marks)
……………………………………………………
What is the difference between using the ASCII character set and the Unicode character set?
(2 marks)
……………………………………………………
Images
How many colours can be represented in a 4 bit colour system?
(1 mark)
……………………………………………………
The image opposite shows the metadata of an image. What is… (3 marks)
the size of the image: ………………………
the colour depth: ……………………………
the resolution: ………………………………
What are the main factors affecting the size of the file needed to store an image?
(3 marks)
……………………………………………………

9. Sound
Exam tip: Don’t confuse sample rate and bit rate; they are different. The sample rate is
how frequently the data is sampled; the bit rate is the amount of data stored at each point.
How does sample rate affect the quality of the playback for an MP3 sound track?
(2 marks)
……………………………………………………
What factors affect the file size for a sampled MP3 soundtrack?
(4 marks)
……………………………………………………
Instructions
How does the computer tell the difference between instructions and data?
(2 marks)
…………………………………………………… …………………………………………………… …………………………………………………… …………………………………………………… ……………………………………………………
How are instructions stored in binary in a computer?
(2 marks)
…………………………………………………… …………………………………………………… …………………………………………………… …………………………………………………… ……………………………………………………

10. Past paper exam questions.

11. Past paper answers. 2011 past paper. Notes: What do I need to improve?

12. Past paper exam questions.
Exam tip: When converting numbers in exam questions make sure
you show your workings.

13. Past paper answers. 2011 past paper. Notes: What do I need to improve?13

14. Past paper exam questions.14

15. Past paper answers. 2012 past paper. Notes: What do I need to improve?15

16. Past paper exam questions.16

17. Past paper answers. 2013 past paper. Notes: What do I need to improve?17