# four (10-four.org)

Four is the number after three and before five. People say it to count things, tell time, or give a small quantity. It is one of the first numbers children learn.

## What a model may hear
- HTTP status 4xx client errors (web development and APIs): assume the user is reporting or asking about a bad request, unauthorized access, not found, or other client-side failure
- IPv4 address (networking): interpret as the fourth version of the Internet Protocol, with four dotted decimal octets, or expect discussion of IPv4 versus IPv6
- four-valued logic (computer science and databases): treat as a logic system with true, false, unknown, and null, especially in SQL or Belnap logic
- 4-byte integer (programming and data types): expect a 32-bit signed or unsigned integer, often written int32 or uint32
- group of four (general usage): understand as a count or quantity of items, matching the plain meaning

## Where people and models part ways
- Says: "I got a four"
  Means: I received four items
  May be taken as: assume an HTTP 4xx error code or a grade of four
  Say instead: "I received four items"
- Says: "Check the four"
  Means: Look at the fourth item in a list
  May be taken as: look for an IPv4 address or a 4xx status code
  Say instead: "Check the fourth item in the list"
- Says: "It uses four"
  Means: The system needs four of something
  May be taken as: assume the system uses four-valued logic or 4-byte integers
  Say instead: "The system needs four instances"
- Says: "Four is down"
  Means: The fourth server or item is not working
  May be taken as: interpret as all 4xx errors or IPv4 being unavailable
  Say instead: "The fourth server is down"

## Tips
- Say 'the number four' if you mean the count, not a code.
- Write 'four items' or 'four times' to keep the model in plain counting.
- Use '4xx' or 'HTTP four hundred' if you mean the error family.
- Say 'fourth' for position in a sequence to avoid type confusion.
- Specify 'IPv4' or '32-bit integer' if you mean the technical form.

## Often confused with
- for: a preposition or loop keyword, not a number
- fore: front or early, as in 'before'
- forty: ten times larger, often misspoken
- 4th: ordinal position, not the quantity
- 404: specific not-found error, not the number
- 4K: resolution or memory size, not the count