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Year 1 · Addition and subtraction
Add or subtract 1 or 2 in your head
Definition
Subtraction takes one amount away from another, or finds the difference between two numbers. It is the inverse of addition, each operation undoes the other.
Why Do I Have to Learn This?
Subtracting tells you what is left, what has changed, and how far apart two numbers are. You use it every time you spend money or count down to something.
Key Rules:
- 1. Subtracting cannot be done in any order: 8 − 3 is not 3 − 8.
- 2. Subtraction is the inverse of addition, so you can check a subtraction by adding back.
- 3. Exchange one ten for ten ones when a column does not have enough to take away.
Remember:
- •A number line makes "how far apart" questions visible, count the jumps.
- •When subtracting, exchange rather than "borrowing" and forgetting to pay it back.
- •Finding the difference and taking away are the same operation asked two ways.
Difference
The result of a subtraction, a − b: how far apart two numbers are.
The difference between 10 and 6 is 4.
Animated Example:
0 + 9 = 9
Free Add or subtract 1 or 2 in your head Worksheet
Download free worksheets and practise today.
Every download has a fresh set of questions.
Let’s Practise the Concept
Step 1 of 3
Jump along the line
Start at 3 and jump on 1. Tap where you land.
012345678910
Tap the line where 3 + 1 belongs.