X Tables
Number Sense

Counting backwards from 20

Prepare for subtraction by stepping back along a number line.

Quick answer

Counting backwards from 20 means starting at 20 and saying the numbers in order going down: 20, 19, 18, 17, and so on until you reach 0. It's like walking backwards on a number line.

Learning outcome

By the end of this page, you will be able to count backwards from 20 and understand how it helps you solve subtraction problems. Success signs:
  • You can say the numbers from 20 down to 0 in order
  • You can count backwards from any number up to 20
  • You can use backwards counting to solve simple subtraction problems
  • You can explain why counting backwards helps with subtraction

Why this matters

Counting backwards from 20 is a key skill that helps you understand subtraction. When you take away objects, you count backwards to find how many are left. It's like walking backwards on a path, and it helps you solve problems like "If I have 10 cookies and eat 3, how many are left?" You start at 10 and count backwards: 9, 8, 7. So you have 7 cookies left. This skill is important for maths at school and for everyday life.

How it works

Counting backwards is like walking backwards. You start at a number and go down by one each time. Let's break it down: Step 1: Start at 20. Step 2: Say the next number down: 19. Step 3: Say the next number down: 18. Step 4: Keep going until you reach 0. You can also think of it as moving backwards on a number line. Each step takes you one number lower.

Examples you can see

Let's look at some examples of counting backwards from 20:
Starting number Counting backwards Final number
20 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 0
15 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 0
10 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0 0
Example 1: You have 8 apples. You eat 3 apples. How many apples do you have left? You start at 8 and count backwards: 7, 6, 5. So you have 5 apples left. Example 2: There are 12 balloons. 5 balloons pop. How many balloons are left? You start at 12 and count backwards: 11, 10, 9, 8, 7. So you have 7 balloons left.

Try it as a mini adventure

Adventure: The Magic Number Trail You are on a treasure hunt! You start at the magic number 20. You must follow the trail by counting backwards. Each step you take takes you one number lower. Your treasure is hidden at 0. Step 1: You start at 20. Step 2: Take your first step and say 19. Step 3: Take your second step and say 18. Step 4: Take your third step and say 17. Step 5: Keep going until you reach 0. Now you have found the treasure! Count backwards from 20 to 0. How many steps did you take? Challenge: Count backwards from 15. How many steps did you take?

Common mistakes

  • Mistake: Forgetting to say the numbers in order. Why it happens: Children may rush or get distracted. Fix: Use your fingers or a number line to help you keep track.
  • Mistake: Counting backwards from 20 but stopping at 10. Why it happens: Children may think the counting stops there. Why it happens: They might not understand that counting continues to 0.
  • Mistake: Jumping numbers, like going from 15 to 13. Why it happens: Children might not be sure of the order. Fix: Practice with a number line or counting objects to help.

Parent and carer guide

Counting backwards from 20 is a skill that helps children understand subtraction. Here's how you can help your child at home: How to help:
  • Use number lines or counting blocks to show how numbers go down.
  • Practice counting backwards from 20 every day. Say it together!
  • Play games where you count backwards. For example, count backwards from 20 while walking.
  • Use real objects like toys or snacks to show subtraction.
  • Ask your child to count backwards from different numbers, not just 20.
What to watch for:
  • Your child might get confused if they don't know the order of numbers.
  • They may rush and skip numbers.
  • They might not understand that counting backwards continues to 0.
How to support:
  • Be patient and encourage them to count slowly.
  • Use visual aids like number lines or counters.
  • Practice with fun activities like singing backwards counting songs.

Practice questions

  1. Count backwards from 20. What number comes after 16?
  2. Count backwards from 15. What number comes after 12?
  3. Count backwards from 10. What number comes after 7?
  4. Count backwards from 20. What number comes after 10?
  5. Count backwards from 18. What number comes after 15?
Answers:
  1. 15
  2. 11
  3. 6
  4. 9
  5. 14

FAQ

What is counting backwards?

Counting backwards means saying numbers in order going down, like 20, 19, 18, 17, and so on.

Why do we count backwards?

We count backwards to help us understand subtraction. When you take away objects, you count backwards to find how many are left.

How can I practice counting backwards?

You can practice by counting backwards from 20 every day. Use your fingers, toys, or a number line to help you.

What comes after 13 when counting backwards?

When counting backwards, the number that comes after 13 is 12.

Is counting backwards the same as subtracting?

Counting backwards helps you understand subtraction. When you subtract, you count backwards to find the answer.