Rounded numbers are easier to work with in your head. They are only approximate.
An exact answer can not be obtained with these numbers. Sometimes an exact answer
is not required.

To round numbers to the nearest thousand, make the numbers whose last three digits
are 001 through 499 into the next lower number that ends in 000. For example, 6424
rounded to the nearest thousand is 6000. Numbers that have the last three
digits of 500 or more should be rounded up to the next even thousand. The number
8788 rounded to the nearest thousand is 9000.