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Number & Arithmetic

What Is Place Value? Digits, Base Ten and Expanded Form

Why the 3 in 4372 is worth 300, how base ten works, and how writing a number in expanded form makes every later method, from column addition to decimals, make sense.

4 min read Supports 3 lessons
In short

Place value is the worth a digit has because of its position in a number. Each place is worth ten times the place to its right.

We write every whole number with just ten symbols: 0,1,2,…,90, 1, 2, \dots, 90,1,2,…,9. The trick that lets ten symbols describe numbers as large as you like is position. The same digit means something different depending on where it sits.

Take the 333 in 437243724372 and the 333 in 333. They look identical, but one is worth three hundred and the other is worth three. That difference is place value.

4thousands×1,000
3hundreds×100
7tens×10
2ones×1

Each column is worth ten times the column to its right.

Why it is called base ten

Count objects one at a time and, as soon as you reach ten, bundle them into a single ten. Ten tens make a hundred, ten hundreds make a thousand, and so on. Every column holds how many bundles of that size you have, and no column ever needs more than nine.

Because each bundle is ten of the one before, our system is called base ten (or the decimal system, from the Latin decem, ten).

1→×1010→×10100→×101000→×1010 0001 \xrightarrow{\times 10} 10 \xrightarrow{\times 10} 100 \xrightarrow{\times 10} 1000 \xrightarrow{\times 10} 10\,0001×10​10×10​100×10​1000×10​10000

Moving one place left multiplies a digit's value by ten.

Expanded form

Writing a number as the sum of what each digit is worth is called expanded form. It turns place value from an idea into something you can see and calculate with.

  1. 437243724372

    Start with the number as we normally write it.

1/4
Key idea

A digit's value is digit × place value. In 85,19685{,}19685,196 the 555 is in the thousands place, so it is worth 5×1000=50005 \times 1000 = 50005×1000=5000.

The role of zero

Zero is what makes the system work. In 405405405, the 000 says there are no tens. Without it, 405405405 and 454545 would look the same. A zero that holds a place open like this is called a placeholder.

Watch out

Zeros inside a number matter; zeros at the very front do not. 040504050405 is still 405405405, but 405040504050 is ten times bigger than 405405405.

Why place value matters later

Almost every written method relies on it. Column addition lines digits up by place so that ones are added to ones and tens to tens. Multiplying by 101010 shifts every digit one place left. Decimals simply carry the pattern on to the right of the units, where each place is a tenth of the one before it.

Worked example

What is the value of the 666 in 2,063,9142{,}063{,}9142,063,914?

  1. 1

    Count places from the right: ones, tens, hundreds, thousands, ten-thousands.

Tip

When numbers get long, group the digits in threes from the right: 2,063,9142{,}063{,}9142,063,914. Each group of three is a new name: thousands, then millions.

Common questions

What is the difference between a digit's face value and its place value?

The face value is just the digit itself, such as 777. Its place value, or value in the number, is the digit multiplied by its position, so the 777 in 437243724372 is worth 707070.

Is place value only for whole numbers?

No. The same pattern continues to the right of the decimal point: tenths, hundredths, thousandths. Each place is still a tenth of the place to its left.

Practise place value

The Place Value lesson has worked examples and unlimited practice that adapts to you.

Open the lesson

On this page

  1. Why it is called base ten
  2. Expanded form
  3. The role of zero
  4. Why place value matters later
  5. Common questions
Lessons on this
  • Place ValueNumber Sense & Arithmetic
  • Decimals & Place ValueDecimals & Percentages
  • Adding & SubtractingNumber Sense & Arithmetic
Related reading3
Ideas this article builds on or leads to.
  • Fractions, Decimals & Percentages
    Decimals Explained: Tenths, Hundredths and Decimal Place Value

    A decimal carries place value past the units: the first place after the decimal point is tenths, then hundredths, then thousandths, each a tenth of the place before.

  • Powers & Roots
    Scientific Notation (Standard Form) Explained with Examples

    Scientific notation, also called standard form, writes a number as a×10na \times 10^na×10n where 1≤a<101 \le a < 101≤a<10 and nnn is a whole number, such as 1.5×1081.5 \times 10^81.5×108 or 4.2×10−44.2 \times 10^{-4}4.2×10−4.

  • Powers & Roots
    What Are Exponents? Powers, Bases and Repeated Multiplication

    An exponent (or power) says how many times to multiply a number, the base, by itself: 25=2×2×2×2×2=322^5 = 2 \times 2 \times 2 \times 2 \times 2 = 3225=2×2×2×2×2=32.