## Rounding Numbers

About how many candies are in the picture to the right?

Like with the candies, sometimes we do not need an exact number. When asked

We can ROUND a number by expressing how big the number is to the nearest ten, hundred, thousand, etc. Understanding place value is important when rounding numbers.

We will explore two ways to estimate numbers using ROUNDING.

Like with the candies, sometimes we do not need an exact number. When asked

*about*how much/big something is we are ESTIMATING. To understand ESTIMATION we must know how to ROUND numbers.We can ROUND a number by expressing how big the number is to the nearest ten, hundred, thousand, etc. Understanding place value is important when rounding numbers.

We will explore two ways to estimate numbers using ROUNDING.

## NUMBER LINE

You can round by locating the number on a number line. Once you know where the number is located, you must ask yourself "Is this number closer to ___ or ___?"

Let's look at an example:

Let's look at an example:

*Round the number 5,478 to the nearest thousand.*As you can see, 5,479 rounds down to 5,000 when rounding to the nearest thousand. The number 5,479 is only 479 away from 5,000 but 521 away from 6,000.

In the same example above, if you were to round to the nearest hundred instead of thousand, you would ask yourslef "Is 5,478 closer to 5,400 or 5,500?" By looking at a number line, you would know that 5,478 rounded to the nearest hundred is 5,500.

What is 5,479 rounded to the nearest ten? If you said 5,480 - you're correct! The number 5,479 is only 1 number away from 5,480 but 9 away from 5,470.

In the same example above, if you were to round to the nearest hundred instead of thousand, you would ask yourslef "Is 5,478 closer to 5,400 or 5,500?" By looking at a number line, you would know that 5,478 rounded to the nearest hundred is 5,500.

What is 5,479 rounded to the nearest ten? If you said 5,480 - you're correct! The number 5,479 is only 1 number away from 5,480 but 9 away from 5,470.

## Rules of Rounding

There are three rules/steps to following when rounding:

1) Circle the digit in the place you are rounding to.

2) Underline the digit to the right of the underlined digit.

3) If the number you underlined is 5 or greater, increase the circled digit by 1. If the number you underlined if less than 5, the circled digit will not change. Finally, change all digits to the right of the circled digit to zeros.

Watch the following videos on ROUNDING:

1) Circle the digit in the place you are rounding to.

2) Underline the digit to the right of the underlined digit.

3) If the number you underlined is 5 or greater, increase the circled digit by 1. If the number you underlined if less than 5, the circled digit will not change. Finally, change all digits to the right of the circled digit to zeros.

Watch the following videos on ROUNDING:

By: khanacademy, http://youtu.be/_qzs1zozTBo

By: MrAguilarTX, http://youtu.be/3afU6JQG15I

## Practice makes perfect!

Visit the following websites to practice rounding:

Rounding Master

Half-Court Rounding

Rounding Master

Half-Court Rounding