Letters are numbers in disguise

Computing · Computer Systems · ages 14-15

Name ______________________ Date ____________

A text file is really a file of numbers drawn by a font.
Circle one: True False
What is a character set?
- A font that draws letters
- An agreed table pairing characters with numbers
- A file of pictures
An early character table gave common letters codes in what range?
- Under 128
- Over a million
- Exactly 8
Two programs open one file with different tables. What happens?
- Wrong characters on screen
- A louder beep
- A bigger file
In a table where A is 65, what code does C get?
- 66
- 67
- 75
Why did the world need a larger standard than one byte per character?
- ASCII numbers grew too small to print
- Scripts beyond Latin and emoji needed far more codes
- Bytes became shorter over time
A file mailed abroad opens as odd symbols. What is the likely cause?
- The text was too long
- The screen is too small
- The two programs used different tables
The same bits can mean a letter or a shade of colour. What decides?
- The size of the font
- The agreed code reading them
- The length of the file name

Answer key

For grown-ups. Fold this page away before handing over the rest.

True · The file holds codes, and the font draws each code as a shape.
An agreed table pairing characters with numbers · It is the shared table that turns characters into numbers and back.
Under 128 · The early table kept every code under 128, fitting one byte each.
Wrong characters on screen · The numbers are read back through the wrong pairings.
67 · Letters in a run sit side by side, so C is two above A.
Scripts beyond Latin and emoji needed far more codes · One byte caps the codes, and the world needed far more characters.
The two programs used different tables · Odd symbols are the classic sign of a table mismatch.
The agreed code reading them · Bits carry no meaning alone. The reading code gives them meaning.