Rounding is a procedure that is used to replace a number with an estimate that looks more friendly than the original number, but at the same time is very close in value to the original number.
For example, we could round 1998 to 2000.
Notice that 2000 is still close to 1998 yet it is more friendly to look at because of all the zeros.
You could also round 8.45982971413 to 8.46.
Notice that 8.46 is still close to 8.45982971413 yet it is more friendly to look at because we were able to get rid of many digits.