Subtraction of Numbers — Grade 2 Mathematics
In Grade 2, we tackle larger subtraction problems involving 2-digit and 3-digit numbers. The key new skill is borrowing (also called regrouping) — what to do when the digit on top is smaller than the digit below. Mastering this unlocks the ability to subtract any numbers!
Column Subtraction — The Method
Set the numbers in a column, larger number on top.
Subtract from right to left: Ones → Tens → Hundreds.
Borrowing: If the top digit in a column is smaller than the bottom digit, borrow 1 ten from the next column to the left. This turns the top digit into (top digit + 10), and reduces the column to the left by 1.
Subtract from right to left: Ones → Tens → Hundreds.
Borrowing: If the top digit in a column is smaller than the bottom digit, borrow 1 ten from the next column to the left. This turns the top digit into (top digit + 10), and reduces the column to the left by 1.
💡 Tip: Always check your subtraction using addition. If 73 − 28 = 45, then 45 + 28 should equal 73. ✅
Worked Examples
Example 1 — 2-Digit Subtraction (No Borrowing)
Work out 87 − 53.
8 7
−5 3
3 4
- Ones: 7 − 3 = 4. Write 4.
- Tens: 8 − 5 = 3. Write 3.
- Answer: 34
Example 2 — 2-Digit Subtraction (With Borrowing)
Work out 73 − 28.
6 13
7 3
−2 8
4 5
- Ones: 3 < 8, so borrow from tens. 3 becomes 13. 13 − 8 = 5.
- Tens: 7 becomes 6 (we lent 1). 6 − 2 = 4.
- Answer: 45
Example 3 — Real World: 3-Digit Subtraction
A shop had 524 biscuits. By the end of the day, 367 biscuits were sold. How many remain?
4 11 14
5 2 4
−3 6 7
1 5 7
- Ones: 4 < 7 → borrow → 14 − 7 = 7
- Tens: 2 becomes 1, but 1 < 6 → borrow → 11 − 6 = 5
- Hundreds: 5 becomes 4. 4 − 3 = 1
- Answer: 157 biscuits remaining 🍪
Practice Questions
1. 96 − 43 = ?
✅ 96 − 43 = 53
2. 81 − 37 = ? (requires borrowing)
✅ 81 − 37 = 44 (1 becomes 11 after borrowing; 11−7=4; 7−3=4)
3. A cinema has 450 seats. 278 are occupied. How many seats are empty?
✅ 450 − 278 = 172 seats empty
4. 700 − 365 = ?
✅ 700 − 365 = 335
5. Check: Is 312 − 147 = 165? Use addition to verify.
✅ 165 + 147 = 312 ✔ Yes, 312 − 147 = 165 is correct!
Key Points to Remember
- Subtract from right to left: Ones → Tens → Hundreds.
- When the top digit is smaller, borrow 1 ten from the column to the left.
- Borrowing adds 10 to the current column and reduces the left column by 1.
- Always check with addition — add the answer back to the number subtracted.
- Subtraction is not commutative: 73 − 28 ≠ 28 − 73.