Subtraction — Maths Topic Journey
Taking away and finding the difference
🟢 Foundation — Subtraction
Learn to subtract single-digit and teen numbers using counting back
Subtracting Single Digits
- Subtraction means taking away.
- When we subtract 7 - 3, we start with 7 and count back 3.
- Example: 7 - 3 = 4
- 9 - 2 = 7
- 8 - 4 = 4
- 10 - 5 = 5
Worked Example: 9 - 5 = ?
- Start at 9
- Count back: 8, 7, 6, 5, 4
- We counted back 5 numbers
- So 9 - 5 = 4
Answer: 4
Tip: Use your fingers to count back. Start at the bigger number and count down!
Counting Back from Teens
- Taking away from 11, 12, 13, 14, 15, 16, 17, 18, 19, 20
- Example: 15 - 2
- Start at 15, count back 2: 14, 13
- 15 - 2 = 13
- 18 - 3 = 15
- 20 - 4 = 16
Worked Example: 17 - 5 = ?
- Start at 17
- Count back 5: 16, 15, 14, 13, 12
- We reached 12
- 17 - 5 = 12
Answer: 12
Tip: Count back carefully on your fingers. One finger for each number you count back.
Sharing and Grouping
- Subtraction can also mean sharing things equally.
- If we have 12 apples to share between 3 people, each person gets 4.
- 12 shared by 3 = 4 each
- We can write: 12 - 4 - 4 - 4 = 0
- Subtraction helps us find groups and equal shares.
Worked Example: There are 16 sweets to share between 4 friends equally. How many does each get?
- Start with 16
- Give 1 to each friend (subtract 4): 16 - 4 = 12
- Give 1 more to each (subtract 4): 12 - 4 = 8
- Give 1 more to each (subtract 4): 8 - 4 = 4
- Give 1 more to each (subtract 4): 4 - 4 = 0
- Each friend got 4 sweets
Answer: 4
Tip: Sharing is dividing equally. It's the same as taking away groups.
Practice Problems
- 6 - 2 = ? — Answer: 4
- 8 - 3 = ? — Answer: 5
- 10 - 4 = ? — Answer: 6
- 14 - 3 = ? — Answer: 11
- 18 - 6 = ? — Answer: 12
🟡 Intermediate — Subtraction
Master column subtraction with borrowing for 2 and 3-digit numbers
Introduction to Column Subtraction
- Column subtraction means writing numbers in columns.
- Ones go in the ones column.
- Tens go in the tens column.
- Subtract the ones first, then the tens.
- Example: 45 - 23
- 45
- - 23
- ----
- 22
Worked Example: 56 - 34 = ?
- Write in columns: 56
- - 34
- Subtract ones: 6 - 4 = 2
- Subtract tens: 5 - 3 = 2
- Answer: 22
Answer: 22
Tip: Line up the numbers by place value. Ones under ones, tens under tens.
Subtraction with Borrowing
- Sometimes we cannot subtract the ones.
- When the ones on top are smaller, we borrow from the tens.
- Example: 42 - 17
- Ones: 2 is less than 7, so we borrow 1 ten
- 2 becomes 12, and 4 tens becomes 3 tens
- Now: 12 - 7 = 5 (ones) and 3 - 1 = 2 (tens)
- Answer: 25
Worked Example: 53 - 28 = ?
- Write in columns: 53
- - 28
- Ones: 3 is less than 8, so borrow from tens
- Borrow 1 ten: 5 tens becomes 4 tens, and 3 becomes 13
- Subtract ones: 13 - 8 = 5
- Subtract tens: 4 - 2 = 2
- Answer: 25
Answer: 25
Tip: If you cannot subtract the ones, borrow 1 ten from the tens column.
3-Digit Subtraction
- For 3-digit numbers, subtract ones, then tens, then hundreds.
- Sometimes you need to borrow from hundreds to tens.
- Example: 345 - 128
- 345
- - 128
- -----
- 217
- Work from right to left: ones, tens, hundreds.
Worked Example: 312 - 147 = ?
- Write in columns: 312
- - 147
- Ones: 2 is less than 7, borrow from tens
- Tens: becomes 0, ones becomes 12. 12 - 7 = 5
- Tens: 0 is less than 4, borrow from hundreds
- Hundreds: becomes 2, tens becomes 10. 10 - 4 = 6
- Hundreds: 2 - 1 = 1
- Answer: 165
Answer: 165
Tip: Borrow from the next column if needed. Work right to left.
Practice Problems
- 47 - 25 = ? — Answer: 22
- 73 - 28 = ? — Answer: 45
- 312 - 145 = ? — Answer: 167
- 450 - 213 = ? — Answer: 237
- 526 - 347 = ? — Answer: 179
🔴 Exam Ready — Subtraction
Subtract money, find differences, and solve word problems with change
Subtracting Money
- Subtracting money works like subtracting decimals.
- Line up the decimal points (the pounds and pence separator).
- Example: £5.30 - £2.15
- £5.30
- - £2.15
- -------
- £3.15
- Always write £ in the answer.
Worked Example: £7.45 - £3.28 = ?
- Write in columns: £7.45
- - £3.28
- Pence: 45 - 28 = 17 pence
- Pounds: 7 - 3 = 4 pounds
- Answer: £4.17
Answer: £4.17
Tip: Line up the decimal points. Always write £ in your answer.
Finding Differences and Change
- Finding the difference is subtraction.
- Change is the money you get back when you buy something.
- Example: Item costs £2.50. You pay with £5.00.
- Change = £5.00 - £2.50 = £2.50
- If you buy for £3.75 and pay with £10.00:
- Change = £10.00 - £3.75 = £6.25
Worked Example: A book costs £4.99. You pay with a £10 note. How much change do you get?
- £10.00
- - £4.99
- -------
- Pence: 100 - 99 = 1 pence (borrow 1 pound)
- Pounds: 9 - 4 = 5 pounds
- Answer: £5.01 change
Answer: £5.01
Tip: Change = money you give - money the item costs
Multi-Step Word Problems
- Some problems need more than one step.
- Read carefully to find what you need to do.
- Example: You have £20. You buy a pen for £3.50 and a book for £5.25. How much do you have left?
- Step 1: Find total spent: £3.50 + £5.25 = £8.75
- Step 2: Find what's left: £20.00 - £8.75 = £11.25
Worked Example: Sarah has 8.75 meters of ribbon. She uses 3.20 meters for a project. How much ribbon does she have left?
- 8.75
- - 3.20
- ------
- Hundredths: 5 - 0 = 5
- Tenths: 7 - 2 = 5
- Ones: 8 - 3 = 5
- Answer: 5.55 meters
Answer: 5.55
Tip: Break word problems into steps. Do subtraction carefully with decimals.
Practice Problems
- £6.50 - £2.30 = ? — Answer: £4.20
- £10.00 - £3.50 = ? — Answer: £6.50
- 7.85 - 2.50 = ? — Answer: 5.35
- 9.20 - 4.75 = ? — Answer: 4.45
- A pen costs £2.45. You pay with £5.00. How much change? — Answer: £2.55