The plus and minus signs story

Quick answer

The plus and minus signs (+ and -) were not always used in maths. They were invented by clever people over 500 years ago to help us write and understand addition and subtraction problems more easily.

Learning outcome

By the end of this page, you will understand how the + and - signs came to be used in maths and why they help us solve problems more clearly.

• You can explain why we use + and - in maths
• You can use + and - to show adding and taking away
• You can see how these signs make maths easier to read
• You can tell a story about how these signs were invented

Why this matters

Understanding how maths symbols like + and - came to be helps you see that maths is not just about numbers – it's about ideas that people thought of over time. Knowing these signs helps you read and write maths problems more easily. This is useful for school work, games, cooking, shopping, and even storytelling!

How it works

Let’s look at how these signs came to be:

1. Long, long ago, people used words like "more" and "less" to show adding and taking away.
2. In the 15th century, a man named Henricus Grammateus started using the + symbol for "more" and the - symbol for "less".
3. Later, a man named Robert Recorde made these symbols more popular by using them in his maths books.
4. Today, we use + and - every day in maths to show adding and taking away.

Examples you can see

Here are some real examples of how + and - are used:

Imagine you are in a treasure hunt. You start with 10 coins. Then you find 5 more coins. You can write this as: 10 + 5 = 15 coins.

Or, if you start with 12 coins and give away 3 coins, you can write: 12 - 3 = 9 coins.

Try it as a mini adventure

The Mystery of the Missing Signs

You are a detective solving a mystery. In an old maths book, you find problems without + or - signs!

1. First problem: 8 4 = 12. What sign should go between 8 and 4?
2. Second problem: 15 6 = 9. What sign should go between 15 and 6?
3. Third problem: 7 3 = 10. What sign should go between 7 and 3?
4. Fourth problem: 14 5 = 9. What sign should go between 14 and 5?

Can you solve the mystery by figuring out which sign makes each problem correct?

Common mistakes

• Mistake: Using + when you should use - (or vice versa)

  Why it happens: Sometimes it's easy to get confused when reading a problem. It helps to think about whether you are adding or taking away.

  Fix: Ask yourself, "Do I have more now or less now?" If more, use +. If less, use -.

• Mistake: Forgetting that 0 + any number = that number

  Why it happens: It can be tricky to think about adding nothing!

  Fix: Remember, if you have 5 apples and add 0 apples, you still have 5 apples. So 5 + 0 = 5.

• Mistake: Thinking - means "take away" only

  Why it happens: Some children only think of - as "taking away" and forget it can also show a difference or "how much more" or "how much less".

  Fix: - shows a change. It can mean "taking away" or "finding the difference".

Parent and carer guide

As a parent or carer, you can help your child understand these signs by:

1. Playing simple maths games using + and - signs, like counting toys or snacks.
2. Reading stories that include adding and taking away, like "The Very Hungry Caterpillar" or "The Greedy Triangle".
3. Using real-life situations to show how + and - work, such as when you're shopping or cooking.
4. Practising writing problems with + and - signs together, like 6 + 3 = 9 or 10 - 4 = 6.
5. Encouraging your child to explain their thinking when solving problems with + and -.

Remember, it’s okay if your child makes mistakes – they’re part of learning. Be patient and keep making maths fun!

Practice questions

1. What sign should go between 5 and 3 in the problem 5 ? 3 = 8?
2. What sign should go between 12 and 7 in the problem 12 ? 7 = 5?
3. What is 0 + 9?
4. What is 11 - 0?
5. What is 6 + 0?

Answers:

1. +
2. -
3. 9
4. 11
5. 6

FAQ

What does the + sign mean?

The + sign means "add" or "more". It shows when you are putting things together.

What does the - sign mean?

The - sign means "subtract" or "take away". It shows when you are removing things.

Who invented the + and - signs?

These signs were invented by people in the 15th century. A man named Robert Recorde helped make them popular in the 16th century.

Why do we use + and - instead of words?

Using + and - makes maths faster and easier to read. Instead of writing "5 more apples and 3 more apples", we can write "5 + 3 = 8".

Are there other symbols in maths?

Yes! There are many symbols in maths, like × for multiplication and ÷ for division. Each one helps us write and understand maths problems more clearly.