Rounding is a skill young elementary school-aged children learn as part of math class. It helps hone math skills with addition, subtraction and estimation. Rounding also may be used in real-life scenarios, such as rounding to the nearest dollar when selling items at a yard sale. In such cases, it's important that both the seller and buyer know of the rounding, as one person is going to get shortchanged by as much as 50 cents.
Determine the total dollar amount you're rounding. Add up all purchases or figures first for sales transactions, as rounding beforehand may produce a different amount than rounding from the total. If just estimating, round each figure beforehand to make it easier to add the dollar amounts together.
Round down for a dollar amount that has 0 to 49 cents. For instance, $51.43 rounds down to $51.
Round up for dollar amounts that have 50 to 99 cents. For instance, $17.50 rounds up to $18.