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Tidying Shelves maths mission

A junior real-world challenge using tidying shelves to practise arrays without feeling like a worksheet.

Quick answer

Tidying shelves is a fun way to learn about arrays – groups of items arranged in rows and columns. By organising toys, books, or clothes, children can see how multiplication works in real life.

Learning outcome

By the end of this page, you will be able to sort items into arrays and use what you know about rows and columns to count them quickly. Success signs:
  • You can make a row of items and count how many are in each row
  • You can make a column of items and count how many are in each column
  • You can work out how many items there are in total by multiplying rows and columns
  • You can solve a simple shelf tidying problem using arrays

Why this matters

Arrays are a way to show numbers as rows and columns – like a grid. They help you count faster and understand multiplication. When you tidy your shelves, you're using arrays without even realising it. This skill helps with everything from sharing snacks to planning your garden.

How it works

Arrays are like a grid. If you have 3 rows and 4 columns, you can make an array with 12 items. Each row has the same number of items, and each column has the same number of items. This makes it easy to count. Let’s break it down:
  1. First, pick a group of items to arrange (like toy cars or books)
  2. Decide how many rows you want (like 3 rows)
  3. Decide how many items go in each row (like 4 cars in each row)
  4. Count how many items you have in total by multiplying rows × columns

Examples you can see

Let’s say you have 12 toy cars and want to put them on a shelf in rows and columns. Example 1: 2 rows and 6 columns
  • Row 1: 6 cars
  • Row 2: 6 cars
  • Total: 2 rows × 6 columns = 12 cars
Example 2: 3 rows and 4 columns
  • Row 1: 4 cars
  • Row 2: 4 cars
  • Row 3: 4 cars
  • Total: 3 rows × 4 columns = 12 cars
Example 3: 4 rows and 3 columns
  • Row 1: 3 cars
  • Row 2: 3 cars
  • Row 3: 3 cars
  • Row 4: 3 cars
  • Total: 4 rows × 3 columns = 12 cars

Try it as a mini adventure

Adventure: The Tidy Shelf Mission You are the shelf tidy-up superhero! You have a box of 24 stickers and want to arrange them on your shelf. 1st time: You make 4 rows with 6 stickers in each row. How many stickers do you have? 4 × 6 = 24 2nd time: You try 3 rows with 8 stickers in each row. How many stickers do you have? 3 × 8 = 24 3rd time: You try 6 rows with 4 stickers in each row. How many stickers do you have? 6 × 4 = 24 4th time: You try 2 rows with 12 stickers in each row. How many stickers do you have? 2 × 12 = 24 5th time: You try 1 row with 24 stickers in it. How many stickers do you have? 1 × 24 = 24 Can you find another way to arrange 24 stickers in rows and columns? Try it!

Common mistakes

  • Mistake: Thinking that 3 rows of 5 items means 3 + 5 = 8 items.
    Why it happens: Mixing up addition and multiplication.
    Fix: Remember that rows × columns = total items. So 3 rows × 5 columns = 15 items.
  • Mistake: Counting the same item twice when making an array.
    Why it happens: Not being careful with rows and columns.
    Fix: Label each row and column clearly to avoid confusion.
  • Mistake: Forgetting that rows and columns must have the same number of items.
    Why it happens: Thinking arrays can be messy.
    Fix: Make sure each row has the same number of items and each column has the same number of items.

Parent and carer guide

To help your child with this activity:
  • Ask your child to show you how they made their arrays using objects like toys or counters
  • Encourage them to count the rows and columns separately before multiplying
  • Ask questions like: “How many rows do you have?” and “How many items are in each row?”
  • Use real-life examples like arranging fruit in a bowl or laying out plates for dinner
  • Don’t worry if they make a mistake – it’s part of learning!

Practice questions

  1. How many items are in an array with 3 rows and 5 columns?
  2. If you have 4 rows and 6 columns, how many items are there in total?
  3. How many items are in 2 rows with 8 columns?
  4. If there are 5 rows and 3 columns, how many items are there?
  5. How many items are in 6 rows with 4 columns?
Answers:
  1. 3 × 5 = 15
  2. 4 × 6 = 24
  3. 2 × 8 = 16
  4. 5 × 3 = 15
  5. 6 × 4 = 24

FAQ

What is an array?

An array is a way to arrange items in rows and columns. Each row has the same number of items, and each column has the same number of items.

Why do we use arrays?

Arrays help us count quickly and understand multiplication. They show us how groups of items work together.

Can I use arrays with any number of items?

Yes! You can make arrays with any number of items. Just decide how many rows and columns you want.

How can I practice arrays at home?

You can make arrays with toys, books, or food. Try arranging them in rows and columns and then multiply to find the total.

What if I can’t make perfect rows and columns?

Arrays don’t have to be perfect. You can still use rows and columns to count, even if the items aren’t perfectly lined up.