Rounding Numbers

In this section, we learn about rounding numbers. Specifically, we will focus on how to round with whole numbers. Often, an exact value is not needed. Let’s suppose we are looking at cars. We might find that a model X car costs $29,755.78, whereas a model G car costs $40,226.38. To make matters simple and easy to remember, we may just say the model X car costs about $30,000 and the model G car costs about $40,000. These values of $30,000 and $40,000 represent approximations. An approximation is an estimate or value that is close, but not exactly the same as the original. Rounding a whole number is a way to give an approximation. To round a whole number, first, we must identify how precise we want our approximation to be. This stems from giving a round off place. Once this is known, we begin our procedure:

1. Identify the digit in the round off place
2. Move one digit right:
   • If this digit is 4 or less, we keep the digit in the round off place as is and change every digit that follows into a zero
   • If this digit is 5 or greater, we add one to the digit in the round off place and change every digit that follows into a zero.

Example 1: Round 326 to the nearest ten
326 - The 2 is the digit in the round off place
326 - The 6 is one digit to the right of the 2, this digit is in the category of 5 or greater. For this scenario, we add one to the digit in the round off place (2). So 2 + 1 = 3. The digit in the tens place will be changed into a 3 and the digit that follows is changed into a 0.
326 Rounded to the Nearest Ten is 330