To eliminate rightmost digits in a number when absolute precision is not required or used. One of the most common uses of rounding is with dollar amounts, which can result in more than two decimal places after a division. Following are four of many rounding methods:

  Round Half Up    3.455 -> 3.46
                   3.454 -> 3.45

  Round Half Down  3.455 -> 3.45
                   3.456 -> 3.46

  Round Up         3.456 -> 3.46
                   3.453 -> 3.46

  Round Down       3.458 -> 3.45
                   3.453 -> 3.45