Rounding Numbers Lesson

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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:

- Identify the digit in the round off place
- 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

Rounding Numbers Resources:

Videos:

Khan Academy - Video
Khan Academy - Video
Math Antics - Video
Text Lessons:

Ask Dr. Math - Text Lesson
Math is Fun - Text Lesson
Monterey Institute - Text Lesson
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