X Tables
Maths Adventures

Ocean maths quest: place value

A story-led junior maths adventure using reefs, ships and underwater maps to decode big numbers by hundreds, tens and ones.

Quick answer

Place value helps you understand how many hundreds, tens, and ones are in any number. When you see the number 347, it means 3 hundreds, 4 tens, and 7 ones. This is how we can read and write big numbers by breaking them down into smaller parts.

Learning outcome

By the end of this page, you will be able to split any number into hundreds, tens, and ones, and use this to understand how big numbers work. Success signs:
  • You can say how many hundreds, tens, and ones are in a number like 562
  • You can build numbers using base-10 blocks or drawings
  • You can compare numbers by looking at how many hundreds, tens, and ones they have
  • You can write numbers in expanded form like 562 = 500 + 60 + 2

Why this matters

Place value is like a secret code that helps us understand big numbers. When you go shopping, you use place value to know if £347 is more than £298. When you're on an ocean adventure, you might read a treasure map that shows coordinates like 456 – this means 4 hundreds, 5 tens, and 6 ones. Understanding place value helps you do maths with bigger numbers, and it's the foundation for learning about decimals, money, and even time!

How it works

Let's imagine you're on an underwater treasure hunt. You find a map that shows a chest at location 789. How do you know what this number means? Every number has a special place for hundreds, tens, and ones:
  • The hundreds place is the first digit from the left
  • The tens place is the second digit from the left
  • The ones place is the third digit from the left
To break down 789:
  1. Look at the first digit: 7 – this is 7 hundreds, or 700
  2. Look at the second digit: 8 – this is 8 tens, or 80
  3. Look at the third digit: 9 – this is 9 ones, or 9
So, 789 = 700 + 80 + 9

Examples you can see

Let’s explore more numbers together, using our ocean adventure theme. Example 1: The Coral Reef You swim past a reef and see 243 coral branches. How do we break this down?
  • 2 hundreds = 200
  • 4 tens = 40
  • 3>
So, 243 = 200 + 40 + 3 Example 2: The Shipwreck A sunken ship has 506 treasure coins. What does this mean?
  • 5 hundreds = 500
  • 0 tens = 0
  • 6>
So, 506 = 500 + 0 + 6, or simply 500 + 6 Example 3: The Underwater Cave You find a cave with 1000 shells. This is a big number!
  • 1 thousands = 1000
  • 0 hundreds = 0
  • 0 tens = 0
  • 0>
So, 1000 = 1000 + 0 + 0 + 0 You can also draw this like a treasure chest with 1000 coins, or imagine 1000 blocks in a big pile.

Try it as a mini adventure

Adventure: The Ocean Map Challenge You are a young explorer on a mission to decode a treasure map. The map shows three numbers that you must break down into hundreds, tens, and ones. Step 1: You find a number 357. How many hundreds, tens, and ones are there?
  • Hundreds: ?
  • Tens: ?
  • Ones: ?
Step 2: You find another number 602. What does this mean?
  • Hundreds: ?
  • Tens: ?
  • Ones: ?
Step 3: You find a number 910. What are the hundreds, tens, and ones?
  • Hundreds: ?
  • Tens: ?
  • Ones: ?
Step 4: Write each number in expanded form.
  • 357 = ? + ? + ?
  • 602 = ? + ? + ?
  • 910 = ? + ? + ?
Step 5: Compare your numbers. Which is the biggest? Which is the smallest?

Common mistakes

  • Mistake: Thinking 400 means 4 hundreds and 4 tens. Why: Confusing the place values. Fix: Remember: 400 = 4 hundreds, 0 tens, 0 ones.
  • Mistake: Writing 567 as 500 + 60 + 70. Why: Adding a zero by mistake. Fix: Double-check that 7 is in the ones place, not the tens place.
  • Mistake: Counting from left to right as ones, tens, hundreds. Why: Not understanding the place value order. Fix: Always start from the left and move right: hundreds, tens, ones.

Parent and carer guide

To help your child understand place value:
  1. Use physical objects like base-10 blocks or counting bears to show hundreds, tens, and ones
  2. Ask your child to explain how many hundreds, tens, and ones are in numbers like 426
  3. Play games like “Guess the number” where you give clues like “This number has 3 hundreds and 7 ones”
  4. Use everyday items: if you have 563 stickers, count how many groups of 100, 10, and 1 there are
  5. Practice writing numbers in expanded form, like 563 = 500 + 60 + 3
If your child gets confused:
  • Revisit the concept with smaller numbers first
  • Use visual aids like charts or drawings
  • Don’t rush – take time to make sure they understand each step

Practice questions

  1. Break down the number 432 into hundreds, tens, and ones.
  2. Write 759 in expanded form.
  3. How many hundreds, tens, and ones are in 208?
  4. Compare 345 and 354. Which is bigger?
  5. What number has 6 hundreds, 0 tens, and 9 ones?
Answers:
  1. 4 hundreds, 3 tens, 2 ones
  2. 700 + 50 + 9
  3. 2 hundreds, 0 tens, 8 ones
  4. 354 is bigger
  5. 609

FAQ

What is place value?

Place value tells us the value of each digit in a number based on its position. In the number 347, the 3 is in the hundreds place, the 4 is in the tens place, and the 7 is in the ones place.

Why is understanding place value important?

Place value helps us read, write, and compare big numbers. It's the foundation for learning addition, subtraction, multiplication, and division with larger numbers.

How can I help my child at home?

You can use everyday objects like coins, blocks, or counters to show how many hundreds, tens, and ones make up a number. Ask questions like “How many tens are in 427?” or play number games.

Can I use place value with numbers bigger than 1000?

Yes! The same pattern continues. After ones, tens, and hundreds, comes thousands, then ten thousands, and so on.

What if my child gets confused with zeros?

Zeros in place value are important – they show that a place is empty. For example, in 406, the 0 in the tens place means there are no tens. Practice with numbers that have zeros to build confidence.