Understanding Place Value - Complete Interactive Lesson
Part 1: What Place Value Means
๐ข Understanding Place Value
Part 1 of 5 โ What Place Value Means
Topics in This Part
| Section |
|---|
| Digits vs. Numbers |
| The Place-Value Columns |
| Finding a Digit's Value |
๐ Key Concept: In our number system, the position of a digit tells you its value. The same digit can mean , or , or โ it all depends on which place it sits in.
Digits vs. Numbers
A digit is one of the ten symbols we write numbers with:
The Place-Value Columns
Reading from the right, the columns grow by ten each step:
| Place | Millions | Hundred-thousands | Ten-thousands | Thousands | Hundreds | Tens | Ones |
|---|---|---|---|---|---|---|---|
| Value of one |
Concept Check ๐ฏ
Finding a Digit's Value
To find what a digit is worth, multiply the digit by the value of its place.
Example: the value of in
The sits in the place, so its value is:
Find the Value ๐งฎ
Write the value of the underlined digit (not just the digit).
1) In , the is worth 2) In , the is worth In , the is worth
Putting It Together
For any digit, ask two questions:
- Which place is it in? (Count from the ones place on the right.)
- What is one of that place worth? (, , , , โฆ)
Multiply, and you have the digit's value.
๐ One last reminder: The places, right to left, are ones, tens, hundreds, thousands, ten-thousands, hundred-thousands, millions. Each is ten times the one before it.
Name That Place ๐ฝ
For the number , choose what each digit means.
Part 2: Three Ways to Write a Number
๐ข Understanding Place Value
Part 2 of 5 โ Three Ways to Write a Number
๐ The Idea: Every whole number can be written three ways โ as digits (standard form), as a sum of place values (expanded form), and in words (word form). They all name the same number.
The Three Forms
| Form | What it looks like | Example for |
|---|---|---|
| Standard form | the digits, with commas | |
| Expanded form | a sum of each place's value |
Part 3: The "Ten Times" Rule
๐ข Understanding Place Value
Part 3 of 5 โ The "Ten Times" Rule
๐ Why it works: Each place is worth ten times the place on its right. So the same digit is worth ten times more each step you move it to the left.
A Digit Is 10 Times Bigger to the Left
Look at the digit as it slides one place to the left:
| Number | Place of the | Value of the |
|---|---|---|
Part 4: Comparing, Ordering & Rounding
๐ข Understanding Place Value
Part 4 of 5 โ Comparing, Ordering & Rounding
๐ Big Payoff: Place value lets you compare any two numbers, put a list in order, and round to a friendly number โ all by looking at digits one place at a time.
Comparing Numbers
To compare two whole numbers, line them up and compare from the left:
- The number with more digits is larger.
- If they have the same number of digits, compare the leftmost place. The bigger digit wins.
- If those digits tie, move one place right and compare again.
We write comparisons with these symbols:
| Symbol | Means |
|---|---|
| is greater than | |
Part 5: Mixed Practice & Mastery Check
๐ข Understanding Place Value
Part 5 of 5 โ Mixed Practice & Mastery Check
You can now (1) name a digit's place and value, (2) write numbers in standard, expanded, and word form, (3) use the "ten times" rule, and (4) compare, order, and round. Let's put it all together.
Quick Reference
| Goal | Key move |
|---|---|
| Find a digit's value | digit place value (e.g. in tens ) |