Rounding Using a Number Line

Rounding with a vertical number line

Created by Mrs. Spence

Rounding

We use rounding techniques to make quick estimates in our calculations.

Martha has $2,304 in the bank, and Mary has $4,821. Martha has about $2,000 and Mary has about $5,000. Together, they have about $7,000.

537

The school sold 537 tickets for the concert. About how many tickets is that? Round to the nearest hundred.

Multiple Choice

How many hundreds do we have? That will be the number on the bottom of the number line?

• 600

• 400

• 500

• 530

537

Our number has a 5 in the hundreds place. That means the bottom number is 500.

Multiple Choice

What is 100 more than 500? That will be the number at the top of the number line.

• 600

• 400

• 500

• 530

537

One hundred more than 500 is 600. That is what goes at the top of the number line.

Multiple Choice

When rounding 537, what is the halfway point?

• 505

• 550

• 605

• 650

Multiple Choice

What does 537 rounded to the nearest hundred round to?

• 500

• 600

Round Down

537 is less than halfway to 600, so it will round to about 500.

4,294

There are 4,294 students at Sparter Middle School. About how many students is that? Round to the nearest thousand.

Multiple Choice

How many thousands do we have? That will be the number on the bottom of the number line?

• 4,000

• 6,000

• 5,000

• 3,000

4,294

Our number has a 4 in the thousands place. That means the bottom number is 4,000.

Multiple Choice

What is 1,000 more than 4,000? That will be the number at the top of the number line.

• 4,000

• 6,000

• 5,000

• 3,000

4,294

When you add 1,000 more to 4,000 you get 5,000. That will be the number that goes at the top of the number line.

Multiple Choice

When rounding 4,294 to the nearest thousand, what is the halfway point on our vertical number line?

• 4,005

• 4,500

• 4,050

• 5,400

Multiple Choice

What does 4,294 rounded to the nearest thousand round to?

• 4,000

• 5,000

Round Down

4,294 is less than halfway to 5,000, so it will round to about 4,000.

18,765

There are 18,765 cans collected for the school fundraiser.  About how many cans is that? Round to the nearest ten thousand.

Multiple Choice

How many ten thousands do we have? That will be the number on the bottom of the number line?

• 10,000

• 18,000

• 20,000

• 17,000

18,765

We have one ten thousand. That means that the bottom number is 10,000.

Multiple Choice

What is one ten thousand more than 10,000? That will be the number that goes on the top of the number line.

• 19,000

• 20,000

• 30,000

• 11,000

18,765

When you add ten thousand more to 10,000 you get 20,000. That will be the number that goes at the top of the number line.

Multiple Choice

When rounding 18,765 to the nearest ten thousand, what is the halfway point on our vertical number line?

• 10,005

• 10,050

• 10,500

• 15,000

Multiple Choice

What does 18,765 rounded to the nearest ten thousand round to?

• 10,000

• 20,000

Round Up

18,765 is more than halfway to 20,000, so it will round to about 20,000.