Written Subtraction Algorithm
Subtract column by column borrowing from the next place when needed.
Key idea
Subtract column by column borrowing from the next place when needed.
In depth
Subtract column by column from the right. If the top digit is smaller, borrow: take one from the next place (worth ten of this place) and add it here.
Worked example
502 − 267: borrow across the zero to get 4 hundreds and 10 tens, then 9 tens and 12 ones. 12−7=5, 9−6=3, 4−2=2. Answer 235.
Real-world uses
- Working out balances in a bank statement or the difference between two large distances
Common mistake
Forgetting to reduce the digit you borrowed from, especially across zeros.
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 Written Subtraction Algorithm?
Subtract column by column borrowing from the next place when needed. It is a topic at the beginner level in Arithmetic & Number Sense.
Where is Written Subtraction Algorithm used in real life?
Real-world examples: Working out balances in a bank statement or the difference between two large distances.
What should I learn before Written Subtraction Algorithm?
Make sure you are comfortable with Written Addition Algorithm, the previous topic in Arithmetic & Number Sense.
What is a common mistake with Written Subtraction Algorithm?
Forgetting to reduce the digit you borrowed from, especially across zeros.
How can I practise Written Subtraction Algorithm?
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 Written Subtraction Algorithm?
Move on to Long Multiplication 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.