Rounding Whole Numbers

Learn how to round whole numbers to the nearest ten, hundred, or thousand.

Elementary15 minLesson
Printable worksheet

Definition

Rounding means replacing a number with a nearby number that is easier to work with. We round to a specific place value like tens, hundreds, or thousands.
The Rounding Rule:
  1. 1.Look at the digit to the right of the place you're rounding to
  2. 2.If that digit is 5 or more, round up
  3. 3.If that digit is 4 or less, round down
Round 47 to the nearest ten: 47→50\text{Round } 47 \text{ to the nearest ten: } 47 \rightarrow 50
Round 43 to the nearest ten: 43→40\text{Round } 43 \text{ to the nearest ten: } 43 \rightarrow 40

Try it now

Round 3434 to the nearest ten.

Worked Examples

Round 6767 to the nearest ten.
1

Find the tens place

In 6767, the tens digit is 66 → Tens place = 66
2

Look at the digit to the right (ones place)

The ones digit is 77 → Deciding digit = 77
3

Apply the rounding rule

Since 7≥57 \geq 5, we round UP
4

Round up to the next ten

66 tens becomes 77 tens, ones become 00 → 67→7067 \rightarrow 70

Common Mistakes

Looking at the wrong digit when rounding

Why it's wrong: Students sometimes look at the digit IN the rounding place instead of the digit to its RIGHT.

Correct: Always look at the digit ONE PLACE TO THE RIGHT of where you're rounding. For rounding to tens, look at the ones digit.

Forgetting to change digits to the right to zeros

Why it's wrong: When rounding 438438 to hundreds, some write 430430 instead of 400400.

Correct: After rounding, ALL digits to the right of the rounding place become zeros.

Rounding down when the digit is exactly 5

Why it's wrong: Some students think 5 is 'in the middle' so it could go either way.

Correct: The rule is '5 or more, round up.' The digit 5 ALWAYS means round up.

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Practice Problems

15 problems
Problem 1 of 15
Easy
Round 3434 to the nearest ten.

Why It Matters

Rounding is a powerful skill you'll use every day:
  • Shopping: Estimating if you have enough money for items costing 24, 18, and 33 dollars (roughly 20 + 20 + 30 = 70 dollars)
  • Time: Saying a trip takes "about 2 hours" instead of 1 hour and 52 minutes
  • Population: Saying a city has "about 500,000 people" instead of 487,293
  • Distance: Saying the school is "about 800 meters" away instead of 783 meters
Rounding makes numbers easier to work with mentally!

Real World Applications

Estimating Shopping Totals

Round prices to quickly estimate if you have enough money.

Example:

Items cost 23 dollars, 47 dollars, and 31 dollars. Round each: 20 + 50 + 30 = about 100 dollars total.

1Try It Yourself

You're buying school supplies: a notebook for 7 dollars, pens for 4 dollars, and a backpack for 38 dollars.

Round each price to the nearest ten and estimate the total.

Step 1: Write the mathematical expression

Round and add: 7→7 \rightarrow ?, 4→4 \rightarrow ?, 38→38 \rightarrow ?

Reporting Large Numbers

News and statistics often use rounded numbers for clarity.

Example:

A concert had 23,847 attendees. The news reports 'about 24,000 people attended.'

2Try It Yourself

A school has exactly 1,247 students enrolled.

How would you report this to the nearest hundred?

Step 1: Write the mathematical expression

Round 1,2471{,}247 to the nearest hundred

Key Takeaways

  • 1Rounding replaces a number with a simpler, nearby number
  • 2Look at the digit to the RIGHT of the place you're rounding to
  • 3If that digit is 5 or more, round UP. If it's 4 or less, round DOWN
  • 4After rounding, all digits to the right become zeros
  • 5Rounding helps with estimation and makes mental math easier

Frequently Asked Questions

This is a mathematical convention that ensures consistency. Since 5 is exactly in the middle, mathematicians agreed to always round up in this case. This is called 'round half up' and is the most common rounding rule.
This is a mathematical convention that ensures consistency. Since 5 is exactly in the middle, mathematicians agreed to always round up in this case. This is called 'round half up' and is the most common rounding rule.
Yes! You can round to tens, hundreds, thousands, ten-thousands, or any place value. The same rule applies: look at the digit to the right and decide whether to round up or down.
It depends! When you round up, the rounded number is larger. When you round down, it's smaller. For example, 67 rounded to 70 is larger, but 43 rounded to 40 is smaller.
Today's challengeOne problem, three tries

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