Subtraction is simply the process of taking one quantity and removing part of it to work out what is left. It is the opposite of addition because we are reducing the value of the number rather than increasing it by adding more numbers.
You can subtract more than one number away from each other, but this usually involves using parenthesis and understanding number facts like number order.
It’s a great idea to introduce subtraction with some examples. There are lots of different ways we can think about teaching subtraction. Talking about a few other methods is a good way to build confidence when children learn about removal.
Showing Subtraction in Maths
Subtraction is usually written with a minus sign between the two subtraction terms. This is because the language of these terms comes from the Latin language. For example, the word removal is an English word, but it comes from the Latin verb subtrahend, where ‘sub’ means ‘from under’ and ‘there’ means to pull. This means the word subtract means to ‘draw from below’ or ‘to take away.’
Terms for Subtraction in Maths
There are lots of terms for subtraction in maths. We must note them to know when subtraction calculations are being discussed or referred to. In addition, they are good cues for children to watch out for in word problems so that they know which operations they need to use.
One of the most common words for subtraction is ‘taking away.’ As you remove the value of one number from another, you take them away from each other. So if we start with six chocolate bars and four remaining, we’ve taken away 2.
Sometimes we focus on subtraction as ‘finding the difference.’ This is because we take one number away from the other and are left with the difference. This focuses more on the answer itself than the equation. The answer is the difference between our original two or more numbers. For example, when we took away two chocolate bars, the difference between 6 and 4 was 2.
Other terms for subtraction in maths are minus, decrease and deduct. These are great terms for children to use when building a number sentence.
More Complicated Terms for Subtraction
Sometimes, however, terms for subtraction in maths mean the numbers you are working with themselves rather than the removal process or the result. These terms for subtraction are called the minuend and subtrahend. The minuend is the first number, the number which you take the other away from. The subtrahend is the subtracted number, the one you take away. Then, of course, we are left with the difference.
Teaching Subtraction as an Inverse of Addition
When children are first introduced to numbers and counting, we always ten to start by counting upwards: 1, 2, 3, 4, 5. Naturally, we usually learn about addition (increasing values) before subtraction.
Having a good grasp of addition can help children when they learn about subtraction, as they can think of inverting operations like this:
2 + 3 = 5
5 – 2 = 3
You can easily demonstrate this principle using objects. Show children how to physically add or remove some from a set, using addition and subtraction vocabulary as you go.
Teaching Subtraction Using a Number Line
Number lines can provide a clear visual representation to help you demonstrate subtraction to children. In addition, number lines are easy to understand and are something children will meet in school from Year 1.
Encourage children to find their starting point on the number line and then count down to find their answer. They can also learn subtraction facts with numbers up to 20, such as 20 – 3 = 17.
This is a great starting point for simple sums before children move on to dealing with larger numbers.
Teaching Subtraction Vocabulary
Talking about subtraction differently is a great way to help children grasp its concept. Here are many examples of how to phrase a subtraction problem for children.
- What is the difference between 7 and 3?
- Take away two from 8.
- What is 9 minus 2?
- Decrease 11 by 5.
- If I take three from 8, how many are left over?
- How much is less four than 10?
- Subtract eight from 12.
Why not ask children to list as many ways to describe subtraction as possible? It is a good idea to test their knowledge with simple questions like this to develop their maths confidence.
