- Determine the two consecutive multiples of 1,000 that bracket 21,391
- 21,391 is between 21,000 and 22,000
- 21,500 is the midpoint between 21,000 and 22,000
- As illustrated on the number line, 21,391 is less than the midpoint (21,500)
- Therefore, 21,391 rounded to the nearest thousand = 21,000
