It is not given till which place estimation has to be done.
Estimated Number of People who attended the football game friday night=12,000
⇒ If Estimation is done using ones
Then, Actual number of people at the game will be
11,995 ≤ Spectator ≤ 12,004
⇒If Estimation is done using Tens
Then, Actual number of people at the game will be
11,950 ≤ Spectator ≤ 12,049
⇒If Estimation is done using Hundreds
Then, Actual number of people at the game will be
11,500 ≤ Spectator ≤ 12,499