Subtraction
Taking one quantity away from another to find the difference.
Key idea
Taking one quantity away from another to find the difference.
In depth
Subtraction finds the difference, or the missing part: a − b = c means b + c = a. It can be seen as removing, or as the distance between two points on a number line. Because it is the inverse of addition, you can always check your answer by adding back.
Worked example
83 − 29 = 54. Check: 54 + 29 = 83.
Formula
Real-world uses
- Working out change from a payment
- Finding how many days remain until an event
- Measuring the gap between two scores
Common mistake
Subtracting the smaller digit from the larger in every column regardless of order. Borrow instead.
How to learn this
- Read the key idea and say it in your own words.
- Work through the worked example, then try a similar problem.
- Use the interactive lesson’s visual and mini-quiz to check the pattern.
Frequently asked questions
What is Subtraction?
Taking one quantity away from another to find the difference. It is a topic at the beginner level in Arithmetic & Number Sense.
What is the formula for Subtraction?
The key formula is a − b = c.
Where is Subtraction used in real life?
Real-world examples: Working out change from a payment; Finding how many days remain until an event; Measuring the gap between two scores.
What should I learn before Subtraction?
Make sure you are comfortable with Addition, the previous topic in Arithmetic & Number Sense.
What is a common mistake with Subtraction?
Subtracting the smaller digit from the larger in every column regardless of order. Borrow instead.
How can I practise Subtraction?
Open the interactive lesson, play with the visual, then answer the three-question mini-quiz. Getting two right marks the topic complete.
What comes after Subtraction?
Move on to Properties of Addition next.
Related beginner topics in Arithmetic & Number Sense
- Counting & Cardinality – Assigning one number word to each object to find how many there are.
- Place Value – The value of a digit depends on its position: ones, tens, hundreds and so on.
- Number Line – A line where numbers are placed in order at equal spacing to compare and add them.
- Comparing Numbers – Use <, > and = to say which number is smaller, larger or equal.
- Ordering Numbers – Arranging numbers from least to greatest or the reverse.
- Even and Odd Numbers – Even numbers divide by 2 with no remainder; odd numbers leave remainder 1.