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Stage 10 of 20

Two-Digit Minus Single (With Borrow)

When the ones digit is too small, borrow one ten from the tens column. This combines your borrowing skills with two-digit place value.

What You'll Learn

  • Borrow one ten when the ones digit is insufficient
  • Subtract single digits from teen numbers mentally
  • Choose between borrowing and the add-up method

Explanation

For 52 − 7: ones digit 2 is less than 7, so borrow. 52 becomes 40 + 12. 12 − 7 = 5. Tens: 4. Answer: 45.

Add-up alternative: from 7 to 52. 7→10 (3), 10→50 (40), 50→52 (2). Total: 45.

Borrowing once reduces the tens by exactly 1 and adds 10 to the ones. The net change is still the correct difference.

Problems like 40 − 6 require borrowing from a zero tens digit — think of 40 as 30 + 10.

Pro Tips

  • • For numbers ending in 0–4, expect to borrow when subtracting 5 or more.
  • • The add-up method avoids messy borrowing and is preferred by many mental math experts.
  • • Practice both methods and use whichever feels faster for you.

Practice Exercises

Work through each problem mentally. Click "Show Answer" when you're ready to check.

  1. 1. 52 − 7 = ?
  2. 2. 61 − 8 = ?
  3. 3. 40 − 6 = ?
  4. 4. 73 − 9 = ?
  5. 5. 35 − 8 = ?
  6. 6. 50 − 7 = ?
  7. 7. 44 − 9 = ?
  8. 8. 63 − 5 = ?
  9. 9. 31 − 6 = ?
  10. 10. 82 − 9 = ?