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Maths Adventures

Robot maths quest: subtraction

A story-led junior maths adventure using circuits, commands and machine logic to work out what is left after trades, rescues or escapes.

Quick answer

Subtraction is about taking away or finding what is left. In a robot maths quest, you might need to subtract to work out how many energy units are left after a mission, or how many parts you have left after building something.

Learning outcome

By the end of this page, you will understand how to use subtraction to find what is left when you take away or remove some items. You will be able to solve simple subtraction problems using objects, drawings, and numbers. Success signs:
  • You can show subtraction by taking away objects
  • You can solve subtraction problems with numbers up to 20
  • You can use subtraction to solve problems about real-life situations
  • You can explain what subtraction means in your own words

Why this matters

Subtraction is like the opposite of addition. It helps you find out what is left when you take something away. In your robot maths quest, subtraction might help you work out how many batteries are left after using some, how many rescue robots you still have after sending some on a mission, or how many energy units are left after a long journey. Subtraction helps you solve puzzles, plan missions, and make sure you have enough resources. In everyday life, subtraction helps you when you are sharing, saving, or counting money.

How it works

Subtraction is about taking away or finding what is left. It uses the minus sign (–) and the equals sign (=). Here are the steps to understand subtraction:
  1. Start with a number – this is your total amount
  2. Take away some – this is what you are subtracting
  3. Find what is left – this is your answer
For example, if you have 8 robots and 3 are sent on a mission, you can subtract 3 from 8 to find out how many robots are left.

Examples you can see

Let's imagine you are on a robot maths quest and you need to solve subtraction problems. Example 1: Robots and Missions You have 10 rescue robots. 4 robots are sent to help in a flood. How many robots are left?
  • You start with 10 robots
  • You take away 4 robots
  • You have 6 robots left
So, 10 – 4 = 6 Example 2: Battery Power Your robot has 15 energy units. It uses 7 units to move. How many energy units are left?
  • You start with 15 energy units
  • You take away 7 units
  • You have 8 units left
So, 15 – 7 = 8 Example 3: Parts Inventory You have 20 robot parts. You use 12 parts to build a new robot. How many parts are left?
  • You start with 20 parts
  • You take away 12 parts
  • You have 8 parts left
So, 20 – 12 = 8

Try it as a mini adventure

Robot Rescue Mission You are on a mission to save robots from a broken factory. You have 15 robots to rescue, but you can only carry 6 robots at a time.
  • First time: You carry 6 robots. How many are left to carry? 15 – 6 = ?
  • Second time: You carry 4 more robots. How many are left to carry? ? – 4 = ?
  • Third time: You carry the rest. How many robots are left to carry? ? – ? = ?
You need to figure out how many robots are left after each trip to complete your rescue mission.

Common mistakes

  • Mistake: Thinking 7 – 3 = 10 instead of 4.
    Why it happens: Confusing subtraction with addition.
    Fix: Use objects or a number line to count backwards.
  • Mistake: Starting with the smaller number and subtracting the bigger number.
    Why it happens: Not understanding that subtraction means taking away.
    Fix: Always start with the bigger number and take away the smaller number.
  • Mistake: Forgetting to write the minus sign.
    Why it happens: Not paying attention to the symbols.
    Fix: Always look for the minus sign before solving the problem.

Parent and carer guide

As a parent or carer, you can help your child learn subtraction by:
  • Using everyday situations like sharing snacks or counting toys to show subtraction
  • Practising with objects like blocks or counters to make subtraction visual
  • Encouraging your child to explain their thinking when solving subtraction problems
  • Reinforcing that subtraction means taking away or finding what is left
  • Being patient if your child makes mistakes – they are part of learning
Remember to keep the focus on understanding rather than speed. Your child is learning to think about how numbers work, not just get the right answer quickly.

Practice questions

  1. 12 – 5 = ?
  2. 9 – 3 = ?
  3. 14 – 8 = ?
  4. 17 – 9 = ?
  5. 20 – 11 = ?
  6. 6 – 2 = ?
  7. 10 – 7 = ?
  8. 13 – 6 = ?
  9. 16 – 10 = ?
  10. 18 – 12 = ?
Answers:
  1. 7
  2. 6
  3. 6
  4. 8
  5. 9
  6. 4
  7. 3
  8. 7
  9. 6
  10. 6

FAQ

What is subtraction?

Subtraction is the maths operation where you take away some items from a group. It helps you find out what is left after something is removed.

How can I help my child with subtraction?

You can use everyday examples like sharing cookies or counting toys. Use physical objects to show subtraction and encourage your child to explain their thinking.

Why is subtraction important?

Subtraction helps you solve real-life problems like finding out how much money you have left after buying something, or how many robots are left after sending some on a mission.

Can subtraction be done with big numbers?

Yes! Subtraction works with any numbers, from small numbers like 3 – 1 to big numbers like 1000 – 500.

What is the opposite of subtraction?

The opposite of subtraction is addition. While subtraction takes away, addition adds together.