Age 9 guide to written multiplication

Quick answer

Written multiplication is a way to solve big multiplication problems by writing them down in columns and using a step-by-step method. It helps you multiply larger numbers like 24 × 13 without needing to use your fingers or a calculator.

Learning outcome

By the end of this page, you will be able to multiply two-digit numbers using the written method (also called long multiplication).

• You can set up a multiplication problem in columns.
• You can multiply each digit of the bottom number by each digit of the top number.
• You can add the partial products to find the final answer.
• You can use this method to solve real-life problems like calculating the cost of multiple items.

Why this matters

Written multiplication helps you solve bigger multiplication problems that are too hard to do in your head. It's useful for things like calculating how much money you need to buy several items, working out how far you've walked, or even helping in games where you need to score points quickly.

It's also the foundation for more advanced maths you'll learn in later years, like multiplying decimals or working with larger numbers in algebra.

How it works

Written multiplication uses a step-by-step process. Here's how to do it:

1. Write the two numbers one above the other, with the larger number on top.
2. Multiply the bottom number's last digit by each digit of the top number, starting from the right.
3. Write the answer below, lining up the digits properly.
4. Repeat this for the next digit in the bottom number, but write your answer one place to the left.
5. Add all the partial products together to get the final answer.

Let's try it with a simple example: 24 × 13.

Examples you can see

Let’s solve 24 × 13 step by step.

So, 24 × 13 = 312.

Try it as a mini adventure

Adventure: The Market Trip

You are going to the market with your family. You need to buy 24 bags of apples, and each bag costs £13. How much will you spend?

1. Write down the multiplication problem: 24 × 13.
2. Use the written method to solve it.
3. Check your answer with a calculator or by adding 13 twenty-four times.
4. Now, imagine you also want to buy 15 bags of oranges that cost £8 each. How much will that cost?

Great job! You’ve solved real-world problems using multiplication.

Common mistakes

• Mistake: Forgetting to shift the second row when multiplying by the tens digit.
• Why it happens: Kids often forget that when multiplying by 10 or more, the answer must be moved one place to the left.
• Fix: Always add a zero in the units place when multiplying by the tens digit.
• Mistake: Adding the partial products incorrectly.
• Why it happens: Kids might add from left to right instead of right to left, or they might misalign the numbers.
• Fix: Double-check the alignment and add each column carefully, carrying numbers if needed.
• Mistake: Mixing up the order of the numbers.
• Why it happens: Kids sometimes forget which number goes on top and which goes on the bottom.
• Fix: Always put the larger number on top to make the calculation easier.

Parent and carer guide

Helping your child with written multiplication is about patience and practice:

• Start with simple problems like 12 × 3, then move to 24 × 13.
• Use physical objects like blocks or counters to show what each step means.
• Encourage your child to explain each step out loud.
• Don’t rush — take time to check their work together.
• Use real-life examples like shopping or cooking to make it fun.

Remember: Mistakes are part of learning. If your child gets stuck, take a deep breath and work through the steps together.

Practice questions

1. What is 15 × 12?
2. Calculate 23 × 14.
3. Solve 31 × 11.
4. Find the answer to 17 × 16.
5. What is 25 × 13?

Answers:

1. 15 × 12 = 180
2. 23 × 14 = 322
3. 31 × 11 = 341
4. 17 × 16 = 272
5. 25 × 13 = 325

FAQ

What is written multiplication?

Written multiplication is a method of multiplying large numbers by writing them in columns and using a step-by-step process to find the answer.

Why do we use written multiplication?

It helps us solve multiplication problems that are too big to do in our heads, like 45 × 23. It's also a foundation for more advanced maths.

How do I know if I’ve done it right?

Check your answer by using a calculator, or by adding up the partial products again. Make sure the numbers are lined up correctly.

Can I use written multiplication with decimals?

Yes, but you'll learn that later. For now, focus on whole numbers.

What if I make a mistake?

Mistakes are normal and helpful! Try to find where you went wrong and correct it. Ask a grown-up to help if you're stuck.