Place Value and Rounding Numbers

Key concept

Place value is the value of each digit in a number, so in 321 the 3 is worth 300. Each column is worth ten times the one on its right. Rounding numbers makes them simpler: 5 or more rounds up, 4 or less rounds down.

Place Value and Rounding Numbers - introduction visual

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Place Value and Rounding Numbers poster

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Place value chart demonstrating the number 54321 with a breakdown of digits in ten thousands, thousands, hundreds, tens, and ones columns.Place value chart for the Base 10 number system, also called decimal system, with columns for trillions, billions, millions, thousands, H, T, and O.Place value chart showing how to round 5,024,579 to the nearest thousand using digit rules 0-4 down and 5-9 up.Place value chart showing how to round down the number 50,245,798 to 50 million by replacing all digits after the thousand place with zeros.Place value chart showing how to round up the number 50,245,798 to 50,246,000.

What is a Place Value Chart?

  • A place value chart shows the value of each digit in a number.
  • For example, the digit 2 means 20 in tens but 200 in hundreds.

The Base 10 Number System

  • The base 10 system uses the digits 0-9 to make all numbers.
  • Moving a digit left makes the value 10 times bigger (5 → 50 → 500).

How to Round a Number?

  • Find the target place you are rounding to, then look at the digit to the right.
  • If the digit is 5 or more, round up; if it is 4 or less, round down.

What Does Rounding Down Mean?

  • When rounding down, the target digit stays the same and the rest become zeros.
  • For example, 342 rounded to the nearest 10 becomes 340.

What Does Rounding Up Mean?

  • When rounding up, the target digit increases by 1 and the rest become zeros.
  • For example, 685 rounded to the nearest 10 becomes 690.

Practice Questions

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Q1Easy

In the number 3452, which place-value column is the digit 3 in?

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Interactive Activity

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Frequently asked questions

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Place value is the value a digit has because of its position in a number. In 321 the 3 is worth 300, the 2 is worth 20 and the 1 is worth 1. Each column is worth ten times the column to its right. The same digit is worth 20 in the tens column but 200 in the hundreds column.

A place value chart shows the value of each digit by the column it sits in. From the right, the columns are ones, tens, hundreds, thousands and ten thousands, each worth ten times the one before. To find a digit’s value, read its column: in 54,321 the 5 sits in the ten thousands column, so the number reads fifty-four thousand, three hundred and twenty-one.

The 6 in 64 is in the tens column, so its place value is 60. The 4 is in the ones column and is worth 4, and 60 + 4 = 64. The same method works for any number: find the column the digit sits in and multiply. In 370, the 7 is in the tens column, so it is worth 70.

Rounding replaces a long number with a simpler one that is close to it. Look at the digit just after the place you are rounding to. If it is 4 or less, round down: keep the rounding digit and change everything after it to zeros. If it is 5 or more, round up: add 1 to the rounding digit, then change the rest to zeros.

Find the column you are rounding to, then look at the digit to its right. To round 342 to the nearest 10, the tens digit is 4 and the next digit is 2, so it rounds down to 340. For 685, the next digit is 5, so it rounds up to 690. For the nearest 100 or 1,000, check the digit after that column.

Use a price tag. Write a number such as 321 in columns labelled hundreds, tens and ones, and ask what each digit is worth: the 3 means three hundreds, the 2 means two tens, the 1 means one. Then move a digit one column left and show it is worth ten times more.

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