Subtraction — Grade 4 Mathematics
In Grade 4, we subtract 5-digit numbers confidently using column subtraction, and use the efficient counting-up method for mental calculations. We also subtract decimals (money and measures).
Mental Method: Counting Up (Shopkeeper's Method)
Instead of taking away, count up from the smaller number to the larger:
To find 8 003 − 3 678:
3 678 → 3 700 (+22) → 4 000 (+300) → 8 000 (+4 000) → 8 003 (+3)
Total added up = 22 + 300 + 4 000 + 3 = 4 325
To find 8 003 − 3 678:
3 678 → 3 700 (+22) → 4 000 (+300) → 8 000 (+4 000) → 8 003 (+3)
Total added up = 22 + 300 + 4 000 + 3 = 4 325
3 678
+22→
3 700
+300→
4 000
+4 000→
8 000
+3→
8 003
💡 When to count up: Works best when numbers are close together or the larger number has many zeros. For very different numbers, written column subtraction is often cleaner.
Worked Examples
Example 1 — 5-Digit Column Subtraction
Calculate 74 352 − 38 617
TTh Th H T O
6 13 12 14
7 4 3 5 2
− 3 8 6 1 7
3 5 7 3 5
− 3 8 6 1 7
3 5 7 3 5
- O: 2<7 → borrow: 12−7=5
- T: 4−1→ borrow: 14−1−1=12? Check: after borrowing, 14−1=13−1(carried)=12→2? Let's be precise:
- 74 352 − 38 617 = 35 735
- Check: 35 735 + 38 617 = 74 352 ✓
Example 2 — Subtracting Decimals
A coat costs £128.50. Farida has £97.75. How much more does she need?
- 128.50 − 97.75
- Count up: 97.75 → 98.00 (+0.25) → 100 (+2) → 128.50 (+28.50)
- Total: 0.25 + 2 + 28.50 = £30.75
Example 3 — Real World: Stadium Capacity 🏟️
A stadium holds 80 000 fans. 64 837 tickets have been sold. How many unsold?
- 80 000 − 64 837
- Count up: 64 837 → 65 000 (+163) → 80 000 (+15 000)
- Total = 163 + 15 000 = 15 163 tickets
Practice Questions
1. Calculate 56 000 − 28 374.
✅ 27 626 (Check: 27 626 + 28 374 = 56 000 ✓)
2. Use counting up: 10 000 − 4 567.
✅ 4 567 → 4 600 (+33) → 5 000 (+400) → 10 000 (+5 000) = 5 433
3. Calculate £250.00 − £84.65.
✅ £165.35
4. A warehouse had 73 500 items. After a sale 48 763 remain. How many were sold?
✅ 73 500 − 48 763 = 24 737 items
5. Calculate 91 042 − 37 856.
✅ 53 186
Key Points to Remember
- Column subtraction: work right to left, borrow when needed.
- Counting up is efficient when numbers are close together or have many zeros.
- Always check: answer + subtracted number = original.
- For decimals: line up the decimal points before subtracting.
- Estimate first to verify reasonableness of your answer.