Units and data representation

• What is the smallest unit of data in computing?

  Bit
• What does a binary digit represent?

  A binary digit represents two possible states: 1 and 0
• How many bits are in a byte?

  8 bits
• What is a nibble?

  A nibble is four bits or half a byte
• What is the difference between analogue data and digital data?

  Analogue data is a real-life signal that can vary greatly, while digital data is binary data that represents analogue data
• Why must analogue data be converted to digital data?

  Because computers work with digital data
• What device is used to convert analogue signals to digital data?

  Analogue-to-digital converter (ADC)
• What device is used to convert digital signals back to analogue signals?

  Digital-to-analogue converter (DAC)
• What types of data can be represented in binary?

  • Numbers
  • Text
  • Images
  • Sound
• How is data represented in computing?

  All data is represented as binary digits
• What is the role of instructions in computing?


  Instructions act on data in computing
• What is the base of the binary number system?

  Base 2
• How do analogue and digital data interact in computing?

  Analogue data must be converted to digital data for computers to use it
• What is the primary way data is represented in computer systems?


  As binary digits
• Why is it important to convert the capacity of a USB memory stick to the same units as the files being stored?

  To ensure accurate calculations of storage capacity
• How many megabytes are in 1 gigabyte?

  1,000 megabytes
• If you have 150 music files each of 6 megabytes, how much total storage space is required?

  900 megabytes
• What calculation determines how many 6 megabyte files can fit on a 1 gigabyte USB memory stick?

  1000 / 6 = 166.66 files
• How many word processed documents can a 1 gigabyte USB memory stick hold if each document is 50 kilobytes?

  20,000 word processed files
• How many image files can a 1 gigabyte USB memory stick hold if each image file is 100 kilobytes?

  10,000 image files
• How many video files can a 1 gigabyte USB memory stick hold if each video file is 100 megabytes?

  10 video files
• What is the process to calculate how many files can fit on a USB memory stick?

  1. Determine the total size of files to be stored.
  2. Convert the USB capacity to the same unit as the files.
  3. Divide the USB capacity by the size of one file.
• What are the typical sizes of different file types that can be stored on a 1 gigabyte USB memory stick?

  • Word processed document: 50 kilobytes
  • Can hold 20,000 files
  • Image file: 100 kilobytes
  • Can hold 10,000 files
  • Video file: 100 megabytes
  • Can hold 10 files
• What is the number system most commonly used by people?

  Denary
• How many unique digits are in the denary number system?

  10 unique digits (0 to 9)
• What is the binary number system also known as?

  Base 2
• What are the four rules for adding two binary numbers?

  0 + 0 = 0

  1 + 0 = 1

  1 + 1 = 10

  1 + 1 + 1 = 11
• What is the process of adding two binary numbers?

  1. Align the numbers by their least significant bit.
  2. Apply the four binary addition rules.
  3. Carry over if necessary.
  4. Write down the result.
• What is the binary result of adding $01 +$$10$?


  $11$ (which is denary 3)
• What is the binary result of adding $01 +$$101$?


  $110$ (which is denary 6)
• What is the binary result of adding $01010011 +$$01110110$?


  $11001001$ (which is denary 201)
• What is overflow in binary addition?

  Overflow occurs when the result requires more bits than are available.
• What is the largest number that can be recorded using eight bits?

  $11111111$ (denary 255)
• What happens when adding $11111110$ and $00000010$ in an eight-bit system?


  The result is $00000000$ (denary 0) due to overflow.
• How can you check your binary addition results?

  • Convert each binary number to denary.
  • Perform the addition in denary.
  • Compare the results.
• What is the primary number system used by people?

  Denary
• How many unique digits are in the denary number system?

  10 unique digits (0-9)
• What is the binary number system also known as?

  Base 2
• How many symbols does the binary number system contain?

  Two symbols (0 and 1)
• What is hexadecimal also known as?

  Hex