Arithmetic Operations
Decimal Subtraction
Subtracting decimals follows the same column method as subtracting whole numbers. The key rule: align the decimal points before you begin.
The Golden Rule – Align the Decimal Point
8.4 − 3.57 → write as 8.40 − 3.57, align points, then subtract
Padding with Zeros
Add trailing zeros so both numbers have the same number of decimal places.
| Original | Padded |
|---|---|
| 7.5 − 2.38 | 7.50 − 2.38 |
| 5 − 1.234 | 5.000 − 1.234 |
Try It: 20.4 − 7.65
Decimal point alignment
Padding zero
Borrowed digit
Result digit
Click Step 1 or Auto Play to begin!
20.4 − 7.65 = 12.75
Pad 20.4 to 20.40. The ones digit is 0, so borrowing has to reach back through the tens column first — the tricky case of borrowing through a zero.
Pad 20.4 to 20.40. The ones digit is 0, so borrowing has to reach back through the tens column first — the tricky case of borrowing through a zero.
Worked Examples
Easy
9.7 − 4.3: ones 9−4=5, tenths 7−3=4. Answer: 5.4
Medium – With Borrowing
6.32 − 2.87: hundredths 2−7 borrow; 12−7=5. Tenths 2−8 borrow; 12−8=4 (adjusted). Ones 5−2=3. Answer: 3.45
Advanced
12.5 − 8.375: pad 12.500 − 8.375. Work right to left with borrowing. Answer: 4.125
Real-Life Applications
- Calculating change: £10 − £3.47 = £6.53
- Comparing measurements: 2.85 m − 1.6 m = 1.25 m
- Tracking weight loss or gain in health.
Key Takeaways
- Always align decimal points before subtracting.
- Pad with trailing zeros where needed.
- Borrowing works exactly as with whole numbers.
- The decimal point in the answer sits directly below those in the calculation.
Practice: Subtract These Decimals
Two decimals with different numbers of decimal places are shown below. If you get it wrong (or leave it blank), we'll align the decimal points together.
Calculate the difference.