Rounding Numbers

Lesson Plan - Get It!

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How Do You Round Numbers?

Rounding numbers is all about simplifying numbers to make them easier to work with.

You can round numbers to the nearest ten or hundred by using place value.

Here is a breakdown.

Rounding to the Nearest Ten

Look at the digit in the ones place.

If it’s less than 5, round down by keeping the tens place the same.

If it’s 5 or greater, round up by adding 1 to the tens place and changing the ones place to 0.

Rounding to the Nearest Hundred

Now, look at the digit in the tens place.

If it’s less than 5, round down by keeping the hundreds place the same.

If it’s 5 or greater, round up by adding 1 to the hundreds place and changing both the tens and ones places to 0.

Here is an example.

Say you want to round 324 to the nearest ten.

1. Look at the digit in the ones place (4).

2. Since 4 is less than 5, you round down.

3. So, 324 rounded to the nearest ten is 320.

Now, try rounding 478 to the nearest hundred.

1. Look at the tens place (7).

2. Since 7 is greater than 5, you round up.

3. So, 478 rounded to the nearest hundred is 500.

Rounding doesn’t have to be difficult once you know the rules!

Using a Number Line to Round Numbers

A number line is a great tool to help you see rounding in action!

Here’s how to use it.

1. Draw a number line from 0 to 10 (or whatever range you need for the problem).

2. Mark where the number falls.

3. Round to the closest number.

Here is an example.

Round 324 to the nearest ten.

1. Draw a number line between 320 and 330.

2. Find where 324 fits. If the number is closer to 320, round down. If it’s closer to 330, round up.

3. Since 324 is closer to 320, it rounds down to 320.

Try rounding 478 to the nearest hundred.

1. Draw a number line between 400 and 500.

2. Find where 478 fits.

3. Since 478 is closer to 500, round 478 to 500.

Using the number line helps you visualize the process and make sure you’re rounding to the right place!

Keep going in the Got It? section!